Hmm, I haven't noticed high CPU usage, but usually it only leaves me around 500MB actually free RAM, basically the entire rest of it is either in use or cache (often about 15 gigs for cache). Turning on the 64 gig swapfile usually still leaves me with close to no free RAM.

I'll see if it's slow already when I get home, I restarted yesterday. Then I'll try the tricks you suggested. For all I know maybe it's not even KDE itself.

Root and home are on separate NVMe drives and there's a SATA SSD for misc non-system stuff.

GPU is nvidia 3060ti with latest proprietary drivers.

The PC does not sleep at all.

To be fair I also want to upgrade to speed up Rust compilation when working on side projects and because I often have to store 40-50 gigs in tmpfs and would prefer it to be entirely in RAM so it's faster to both write and read.