Perform actions on component initialization in LWC - initialization

Question

I recently started learning LWC. I am working on a requirement in LWC where on component initialization I need to use record Id to get value of numeric field from same object/record, check if it is 100 and display a message on component html. Note - this LWC is used as a quick action of type Screen Action. Following is current implementation which works at times and doesn't (not sure if it is a cache issue).
LWCComponent.html
<template>
<!-- modal start -->
<template if:true={isShowModal}>
<lightning-quick-action-panel header="New Record">
<div class="slds-modal__content modalBodySpinner" style="width: 100%;" id="modal-content-id-1">
<template if:true={isLoaded}>
<lightning-spinner alternative-text="Loading" size="medium" class="spinnerClass"></lightning-spinner>
</template>
<div slot>
<lightning-layout>
<lightning-layout-item size="6" padding="around-small">
<lightning-input label="Record Name" type = "text" value={recordName}></lightning-input>
</lightning-layout-item>
</lightning-layout>
</div>
<template if:true={recordId}></template>
<template if:true={showForm}>
<lightning-input label="Record ID" type="text"></lightning-input>
</template>
<template if:false={showForm}>
<p class="warningP">{restrictMessage}</p>
</template>
<br/>
</div>
<div slot="footer">
<lightning-button variant="neutral" label="Cancel" onclick={closeModal}></lightning-button>
</div>
</lightning-quick-action-panel>
</template>
<!-- modal end -->
</template>
LWCComponent.js
import { LightningElement, track, api, wire } from 'lwc';
import { getRecord, getFieldValue } from "lightning/uiRecordApi";
import NAME from "#salesforce/schema/CustomObject__c.Name";
import CAPACITY from "#salesforce/schema/CustomObject__c.Capacity__c";
import { CloseActionScreenEvent } from 'lightning/actions';
import restrictMessage from "#salesforce/label/c.RestrictWarning";
const fields = [NAME, CAPACITY];
export default class NewClass extends LightningElement {
#track isShowModal = true;
#track showForm = true;
#api recordId;
#track isLoaded = true;
#api capacityVal;
#track warningMsg;
#track retrievedRecordId = false;
#wire(getRecord, {
recordId: "$recordId",
fields
})
custObjRec;
get recordName() {
return getFieldValue(this.custObjRec.data, NAME);
}
renderedCallback() {
if(!this.retrievedRecordId && this.recordId) {
this.retrievedRecordId = true;
this.capacityVal = getFieldValue(this.custObjRec.data, CAPACITY)
if(this.capacityVal == 100) {
this.showForm = false;
this.warningMsg = restrictMessage;
this.isLoaded = false;
}
else {
this.isLoaded = false;
}
}
else {
this.isLoaded = false;
}
}
// method to close modal pop up
closeModal() {
this.dispatchEvent(new CloseActionScreenEvent());
}
}
Any suggestions to make this better?