InDesign 16.2.1 - Performance issues so severe app is unusable.

I have been experiencing severe performance issues with Adobe InDesign recently, and had hoped that the 16.2.1 release would resolve them.  Unfortunately the issues persist.  The application regularly stops responding for 15 - 45 seconds at a time with the following type of interactions:

• Selecting text
• Clicking an input field (ex. Font size) to adjust a setting
• Double-clicking a Page / Master Page to change the active page.
• Adjusting any settings in Preferences

I have taken the following steps to try and address the issue, with no success:

• Uninstalling all Creative Cloud services, and re-installing
• Manually deleting all preferences
• Resetting Preferences via Shift / Command / Control / Option shortcut
• Re-validating all activated fonts, and removing any that have any warnings or errors
• Disabling GPU performance
• Disabling 'Type Contextual Controls'
• Disabling all Pre-Flight features
• NVRAM / SMC Reset

Nothing has resolved the issue, which persists throughout InDesign regardless of whether I am editing an existing document or creating and working with a new document.  I'm at my wit's end as InDesign is essential for my daily workflow.  Below is a breakdown of my system configuration.

• OS: macOS Big Sur v11.3.1
• System: iMac (Retina, 5K, 27", Late 2014)
• Processor: 4Ghz Quad-Core Intel Core i7
• RAM: 32gb 1600 MHz DDR3
• GPU: AMD Radeon R9 M295X 4gb
• HDD: 500 GB SSD, APFS-Format, 313.67 GB free disk space

All Creative Cloud assets are up to date as of 5/23/2021.  Installed Creative Cloud apps / services include:

• Creative Cloud (v5.4.5.550)
• Photoshop (v22.4.1)
• XD (v40.1.22)
• Illustrator (v23.2.23)
• InDesign (v16.2.1)
• Acrobat (v21.0)