Timeline playback is choppy, dropping audio and stuttering frames. Makes it impossible to edit. How do I fix this?

The playback on my timeline is delayed, choppy, and sometimes stops altogether. Video frames drop, audio comes in and out; sometimes the video continues to play in the Program window but the playhead freezes in the timeline and the audio stops. It’s just generally not a smooth playback experience and makes it impossible to edit. (I’m attaching a screen recording.)

I am editing with a SanDisk 4T SDD. My computer is a 2022 MacBook Pro running on an M2 chip. OS is Tahoe 26.2. Premiere version is 26.0.0 (Build 72).

In Premiere, Renderer is set to “Mercury Playback Engine GPU Acceleration (Metal).”

Here is what I’ve tried so far:

-resetting preferences in premiere

-updating my computer software

-updating Premiere

-deleting media cache

-clearing out the hard drive I keep the project on so there is 1T of free space

-reducing playback resolution to ¼

-used the Media Encoder to convert MXF files to Apple ProRes 422 LT codec

I have been editing other projects and have not had any issues.

Can anyone help?