Process Hanging System - how to find?

Yup, no swap.
Which means … aside from oom-killer being able to get rid of things, your system would otherwise be expected to lock up when it reaches the end of its memory.

Theres lots of options for SWAP.

https://wiki.archlinux.org/title/Swap

I usually suggest zram these days unless hibernation is required.

Heres an example that would create zram for swap equal to the size of your memory;

Continuing the discussion from Awful performance since install:

Though that still wont ‘fix’ the runaway memory usage.

For that … please see related threads on pamac as linked above.