Premiere Pro video playback skips frames, lags behind, then stops while audio continues

I need help please.

I can no longer edit in Premiere Pro because (1) the video playback lags WAY behind the audio, at first jumping through a few frames and then stopping altogether while the audio continues. (2) THEN even the audio stops and everything appears locked. None of the editing buttons (e.g. play, stop, etc.) respond – but the save file button works with no lag.

I record mostly with a GoPro, in 4k, and have been doing this for a year without problems. These issues did not happen even last week. I am using the same recording settings as I was using before this started – so the 4k was not causing a problem a week ago (at least any that I noticed).

Here’s what I have done to try and fix the problem – without success:

Upgraded from Windows 10 to Windows 11 (made one vid without problems after this upgrade, so no issues at this point)

Upgraded to Premiere Pro 22.4. (Build 57) (made one vid without problems after this upgrade, so no issues at this point)

Uninstalled and reinstalled Premiere Pro

Adjusted the Premiere sequence to 1920 x 1080 (and inserted the 4k clips into that) to edit them as 1080 – no improvement (maybe some specific settings here would help?)

Tried SET TO FRAME SIZE and SCALE TO FRAME SIZE to adjust the 4k clips to test for improvement – no change (though maybe seemed a little better using “set”?)

Adjusted CPU priority in task manager to HIGH for Premiere Pro

Minimized “RAM reserved for other applications” to 1.5 GB out of 8 GB (in the memory settings of Premiere)

Tried to optimize rendering for MEMORY and then for PERFORMANCE – no change

Deleted media cache files

Reduced playback resolution to ¼ instead of FULL

Scandisk indicated no viruses or malware.

Using ASUS Zenbook13 Intel(R) Core(TM) i7-1065G7 CPU @ 1.30GHz 1.50 GHz; 8 GB RAM

In general, no slowdown problems as long as I have around 100 GB storage available while editing.

I am dead in the water here. Any help would be greatly appreciated. Thanks!!