Problems scrubbing/playback footage in Program Monitor

Hi everyone, 

Having a relatively new problem. For the last few weeks Premiere has stuttered horribly when scrubbing footage in the Program Monitor, or trying to play it at all. I proxy all files before I start editing. This computer has been super fast ever since I bought it but lately, it's made editing very difficult. I feel like I'm using my old 2016 Macbook again. 

Sometimes, I can't even play the timeline correctly. I'll hit play, and the audio plays fine, but the picture is frozen. If I wait 10-20 seconds it might jump ahead in the picture but it won't play smoothly. My sequence isn't that busy, either. There's 2 GoPro clips that are about 20 min long, with shorter GoPro clips laid above those. 

Computer: 2021 MacBook Pro 16"

- M1 Max

- 64GB RAM

- Ventura 13.5.2 (I've heard the Sonoma is riddled with issues)

Premiere version: 23.1.0 Build 86

(I had the newest version and still had this issue. I just reverted back to this version in an attempt to fix it. It helped for five minutes. )

Drive: BRAND new SanDisk Extreme 1TB SSD. I was previously using a Samsung that had been fine but I thought the issue was the drive. 

Monitor: External through an HDMI adapter (the problem persists even without this monitor)

Any advice would be welcomed.