How can we make the combobox as readonly in Salesforce Lightning Web Component?

Sample code:
 
HTML:
<template>
    <lightning-card>
        <lightning-combobox
            name="filter"
            label="Industry"
            value={selectedValue}
            options={options}
            onchange={handlePicklistChange}
            placeholder="Select Industry"
            read-only={readOnlyBool}>
        </lightning-combobox>
        <p slot="footer">
            <lightning-button onclick={enablePicklist} label="Enable"></lightning-button>
            <lightning-button onclick={disablePicklist} label="Disable"></lightning-button>
        </p>
    </lightning-card>
</template>
 
JavaScript:
import { LightningElement, wire } from 'lwc';
import INDUSTRY_FIELD from '@salesforce/schema/Account.Industry';
import { getPicklistValues, getObjectInfo } from 'lightning/uiObjectInfoApi';
import ACCOUNT_OBJECT from '@salesforce/schema/Account';

export default class LightningComboBox extends LightningElement {

    options = [];
    picklistOptions = [];
    selectedValue;
    readOnlyBool = false;

    @wire( getObjectInfo, { objectApiName: ACCOUNT_OBJECT } )
    objectInfo;

    @wire( getPicklistValues, { recordTypeId: '$objectInfo.data.defaultRecordTypeId', fieldApiName: INDUSTRY_FIELD } )
    wiredData( { error, data } ) {

        console.log( 'Inside Get Picklist Values' );

        if ( data ) {
                            
            console.log( 'Data received from Picklist Field ' + JSON.stringify( data.values ) );
            this.options = data.values.map( objPL => {
                return {
                    label: `${objPL.label}`,
                    value: `${objPL.value}`
                };
            });
            console.log( 'Options are ' + JSON.stringify( this.options ) );

        } else if ( error ) {

            console.error( JSON.stringify( error ) );

        }

    }

    handlePicklistChange( event ) {
        
        console.log( 'New Value selected is ' + JSON.stringify( event.detail.value ) );   

    }

    enablePicklist() {
        
        this.readOnlyBool = false;

    }

    disablePicklist() {
        
        this.readOnlyBool = true;

    }


 
JS-meta.xml:
<?xml version="1.0" encoding="UTF-8"?>
<LightningComponentBundle xmlns="http://soap.sforce.com/2006/04/metadata">
    <apiVersion>52.0</apiVersion>
    <isExposed>true</isExposed>
    <targets>
        <target>lightning__Tab</target>
    </targets>
</LightningComponentBundle>

 
Enabled Lightning Combo box
 
 
Disabled Lightning Combo box