Slow when using masking - especially brushes

I've used Lightroom Classic for years, and it's never been this bad. I literally got a new computer just to speed up my workflow. In the last couple of weeks, it's gotten so slow, I can't even use it. It started with slow masking, especially with brushes. But now, even switching to the next picture in the strip takes 5-10 seconds. Cropping? It's not even worth it unless it's really crucial, as it takes forever, especially if I'm straitening it out.

I tried cleaning up my SSD, clearing the LR cache, upping the limit to 25gb, creating a new catalogue, reseting the preferences, swithing off the GPU setting (nothing changed) and then turning it back on, updating my driver from the manufacturer site. Nothing works.

I had Adobe remote access my computer, twice. They did a few things I mentioned above (reset preferences, set my GPU preference to custom, clearing the cache, etc), and they seemed to make it faster for about 15 minutes. Then it's right back to where we started. Now none of those things even make a difference. I'm well above minumum system requirements, but it's even worse than when I used a computer that was below minimum requirements.

I'm so lost on what to do.

Lightroom Classic version: 12.1 [ 202212072312-d7ab524b ]
License: Creative Cloud
Language setting: en
Operating system: Windows 10 - Home Premium Edition
Version: 10.0.19045
Application architecture: x64
System architecture: x64
Logical processor count: 20
Processor speed: 3.6GHz
SqLite Version: 3.36.0
CPU Utilisation: 0.0%
Built-in memory: 65457.6 MB
Dedicated GPU memory used by Lightroom: 3635.6MB / 8032.0MB (45%)
Real memory available to Lightroom: 65457.6 MB
Real memory used by Lightroom: 14159.8 MB (21.6%)
Virtual memory used by Lightroom: 19280.9 MB
GDI objects count: 1076
USER objects count: 2377
Process handles count: 75742
Memory cache size: 575.3MB
Internal Camera Raw version: 15.1 [ 1329 ]
Maximum thread count used by Camera Raw: 5
Camera Raw SIMD optimization: SSE2,AVX,AVX2
Camera Raw virtual memory: 1871MB / 32728MB (5%)
Camera Raw real memory: -2428MB / 65457MB (-3%)
System DPI setting: 144 DPI (high DPI mode)
Desktop composition enabled: Yes
Standard Preview Size: 3840 pixels
Displays: 1) 3840x2160
Input types: Multitouch: No, Integrated touch: No, Integrated pen: No, External touch: No, External pen: Yes, Keyboard: No

Graphics Processor Info:
DirectX: NVIDIA GeForce RTX 3070 (31.0.15.2756)
Init State: GPU for Export supported by default
User Preference: GPU for Export enabled