Populate and iterate through Object in LWC

Originally I tried building a Map and iterating through that to dynamically build a Lightning Accordion with corresponding Sections but I learned that I could not iterate over a Map.

I've tried to create an Object and iterate over that instead but I fear my approach in building the object is stuck in how I would try to do this from an Apex perspective rather than an optimal JS approach.

The optimal data structure for the Object would be something like this:

customObject = {name : perm.outputType, values : [perm]}

This is so all of the permission records of a certain type would be grouped together in an Array and I can loop through those and display them within the section.

Function Code:

  if (this.permissionsObject !== undefined && Object.hasOwn(this.permissionsObject, perm.outputType)) {
    console.log('entered step 1');
    let typeObject = Object.getOwnPropertyDescriptor(this.permissionsObject, perm.outputType);
    console.log(typeObject);
    let arrayValues = Object.values(typeObject);
    Object.defineProperty(this.permissionsObject, perm.outputType, { value: [...arrayValues, perm], configurable: true });
  } else {
    Object.defineProperty(this.permissionsObject, perm.outputType, { value: [perm], configurable: true });
  }

Relevant LWC Html:

<lightning-accordion allow-multiple-sections-open onsectiontoggle={handleSectionToggle}
        active-section-name={activeSections}>
        <template for:each={permissionsObject.key} for:item="perm">
          <lightning-accordion-section label="{perm}">
            <template for:each={perm.values} for:item="permValue">
              <div key={perm.outputUniqueId}>{permValue.outputName}</div>
            </template>
          </lightning-accordion-section>
        </template>
      </lightning-accordion>

Any assistance which could be provided on a more optimal way to approach this from a JS perspective would be great. Thanks!