Add/Remove Rows in Data table in LWC Salesforce

<template>
    <lightning-quick-action-panel header="Manage Contacts">
        <div class="slds-p-around_none slds-m-top_x-small slds-m-bottom_medium slds-m-horizontal_none modalBodyy">
             <template if:true={isLoading}>
                <lightning-spinner alternative-text="Loading" size="medium" class="spinnerClass"></lightning-spinner>
             </template>
             <lightning-card>
                 <lightning-button label="Add Row" slot="actions" icon-name="utility:add" onclick={addRow}></lightning-button>
                <div class="slds-m-around_medium">
                    <table class="slds-table slds-table_cell-buffer slds-table_bordered" aria-labelledby="element-with-table-label other-element-with-table-label">
                        <thead>
                            <tr class="slds-line-height_reset">
                                <th class="" scope="col">
                                    <div class="slds-truncate" title="First Name">First Name</div>
                                </th>
                                <th class="" scope="col">
                                    <div class="slds-truncate" title="Last Name">Last Name</div>
                                </th>
                                <th class="" scope="col">
                                    <div class="slds-truncate" title="Email">Email</div>
                                </th>
                                <th class="" scope="col">
                                    <div class="slds-truncate" title="Stage">Action</div>
                                </th>
                            </tr>
                        </thead>
                        <tbody>
                            <template for:each={records} for:item="obj">
                                <tr class="inputRows" key={obj.Id}>
                                    <th data-label="Opportunity Name" scope="row">
                                        <lightning-input type="text" class="fields" variant="label-hidden" label="First Name" name="FirstName" value={obj.FirstName} data-id={obj.Id} onchange={updateValues}></lightning-input>
                                    </th>
                                    <td data-label="Account Name">
                                        <lightning-input type="text" class="fields" variant="label-hidden" label="Last Name" name="LastName" value={obj.LastName} data-id={obj.Id} onchange={updateValues}></lightning-input>
                                    </td>
                                    <td data-label="Close Date">
                                       <lightning-input type="text" class="fields" variant="label-hidden" label="Email" name="Email" value={obj.Email} data-id={obj.Id} onchange={updateValues}></lightning-input>
                                    </td>
                                    <td data-label="Prospecting">
                                        <lightning-button-icon icon-name="action:delete"  alternative-text="Delete" title="Delete" data-id={obj.Id} onclick={handleDeleteAction}></lightning-button-icon>
                                    </td>
                                </tr>
                            </template>
                        </tbody>
                    </table>
                </div>
            </lightning-card>
        </div>
        <div slot="footer">
            <lightning-button variant="neutral" label="Cancel" onclick={closeAction}></lightning-button> &nbsp;
            <lightning-button variant="brand" label="Save" onclick={handleSaveAction} disabled={isDisable}></lightning-button>
        </div>
    </lightning-quick-action-panel>
</template>

import { LightningElement, api, track, wire } from 'lwc';
import { CloseActionScreenEvent } from 'lightning/actions';
import { ShowToastEvent } from 'lightning/platformShowToastEvent'
import fetchContacts from '@salesforce/apex/ContactController.fetchContacts';
import dmlOnContacts from '@salesforce/apex/ContactController.dmlOnContacts';
import { refreshApex } from '@salesforce/apex';

export default class AccountContactTable extends LightningElement {
    @api recordId;
    @track isLoading = true;
    @track records;
    wiredRecords;
    error;
    @track deleteConatctIds = '';

    //to close quick action
    closeAction(){
        this.dispatchEvent(new CloseActionScreenEvent());
    }

    //to add row
    addRow() {
        let randomId = Math.random() * 16;
        let myNewElement = {Email: "", FirstName: "", Id: randomId, LastName: "", AccountId: this.recordId};
        this.records = [...this.records, myNewElement];
    }

    get isDisable(){
        return (this.isLoading || (this.wiredRecords.data.length == 0 && this.records.length == 0));
    }

    //show/hide spinner
    handleIsLoading(isLoading) {
        this.isLoading = isLoading;
    }

    //update table row values in list
    updateValues(event){
        var foundelement = this.records.find(ele => ele.Id == event.target.dataset.id);
        if(event.target.name === 'FirstName'){
            foundelement.FirstName = event.target.value;
        } else if(event.target.name === 'LastName'){
            foundelement.LastName = event.target.value;
        } else if(event.target.name === 'Email'){
            foundelement.Email = event.target.value;
        }
    }

    //handle save and process dml 
    handleSaveAction(){
        this.handleIsLoading(true);

        if(this.deleteConatctIds !== ''){
            this.deleteConatctIds = this.deleteConatctIds.substring(1);
        }

        this.records.forEach(res =>{
            if(!isNaN(res.Id)){
                res.Id = null;
            }
        });
        
        dmlOnContacts({data: this.records, removeContactIds : this.deleteConatctIds})
        .then( result => {
            this.handleIsLoading(false);
            refreshApex(this.wiredRecords);
            this.updateRecordView(this.recordId);
            this.closeAction();
            this.showToast('Success', result, 'Success', 'dismissable');
        }).catch( error => {
            this.handleIsLoading(false);
            console.log(error);
            this.showToast('Error updating or refreshing records', error.body.message, 'Error', 'dismissable');
        });
    }

    //remove records from table
    handleDeleteAction(event){
        if(isNaN(event.target.dataset.id)){
            this.deleteConatctIds = this.deleteConatctIds + ',' + event.target.dataset.id;
        }
        this.records.splice(this.records.findIndex(row => row.Id === event.target.dataset.id), 1);
    }

    //fetch account contact records
    @wire(fetchContacts, {recordId : '$recordId'})  
    wiredContact(result) {
        this.wiredRecords = result; // track the provisioned value
        const { data, error } = result;

        if(data) {
            this.records = JSON.parse(JSON.stringify(data));
            this.error = undefined;
            this.handleIsLoading(false);
        } else if(error) {
            this.error = error;
            this.records = undefined;
            this.handleIsLoading(false);
        }
    } 

    showToast(title, message, variant, mode) {
        const event = new ShowToastEvent({
            title: title,
            message: message,
            variant: variant,
            mode: mode
        });
        this.dispatchEvent(event);
    }

    updateRecordView() {
       setTimeout(() => {
            eval("$A.get('e.force:refreshView').fire();");
       }, 3000); 
    }
}

.modalBodyy {
    position: relative;
}

<?xml version="1.0"?>
<LightningComponentBundle xmlns="http://soap.sforce.com/2006/04/metadata">
	<apiVersion>51.0</apiVersion>
	<isExposed>true</isExposed>
	<targets>
        <target>lightning__RecordAction</target>
        <target>lightning__RecordPage</target>
    </targets>
	<targetConfigs>
        <targetConfig targets="lightning__RecordAction">
            <actionType>ScreenAction</actionType>
        </targetConfig>
    </targetConfigs>
</LightningComponentBundle>

public class ContactController {
    @AuraEnabled( cacheable = true )
    public static List<Contact> fetchContacts(String recordId) {
        return [SELECT Id, AccountId, FirstName, LastName, Email FROM Contact WHERE AccountId =:recordId LIMIT 100];
    }

    @AuraEnabled
    public static string dmlOnContacts(Object data, String removeContactIds) {
        List<Contact> updateContact = (List<Contact>) JSON.deserialize(JSON.serialize(data), List<Contact>.class);
        List<Contact> deleteContact = new List<Contact>();

        if(String.isNotBlank(removeContactIds)){
            List<Id> contactIds = removeContactIds.split(',');
            deleteContact = [SELECT Id FROM Contact WHERE Id IN :contactIds];
        }

        try {
            if(updateContact != null && !updateContact.isEmpty()){
                upsert updateContact;
            }

            if(deleteContact != null && !deleteContact.isEmpty()){    
                delete deleteContact;
            }
            return 'Success: Contact(s) upsert/delete successfully';
        }
        catch (Exception e) {
            String errorMsg = 'The following exception has occurred: ' + e.getMessage();
            throw new AuraHandledException(ErrorMsg);
        }
       // return '';
    }
}