Only ONE Undo Available. Please help!

[EdwardCPI]

Windows 11 Pro with 48 GB of RAM

InDesign 20.4.1

InDesign is giving me fits. Yesterday it would not recognize certain fonts. So I downgraded from version 20.5 to 20.4.1. That fixed the font problem.

However, now I have a new problem. I can only Undo ONE TIME, or at the most (occasionally 2).

Troubleshooting so far: 

I have restarted InDesign.

Restarted the computer.

Rebuilt preferences and cache using this guide:

https://www.rockymountaintraining.com/adobe-indesign-rebuilding-preferences-cache/

Does anyone know what else I can try to get my unlimited Undos back?

I work at a very busy print shop and this nonsense is just killing me. 

Any help very much appreciated.

UPDATE: it also doesn't seem to want to remember settings, like "Show Import Options" when placing a file. Every time I place a new file I have to check that box--it used to remember my last choice on that.

[EdwardCPI · Accepted solution]

UPDATE: FIXED!

Did some more googling and Gemini suggested unchecking "GPU Performance" in Preferences. I did that and BOOM! I now have multiple undos back and InDesign remembers other settings, like "Show Import Options" when placing graphics.

Hope this can help someone else who has these problems.

What am I losing by unchecking GPU Peformance and why do I have to uncheck that to get multiple undos?