[zsz]

All Affinity software (AFAIK) these days makes extensive use of 3D graphics hardware. The problems you're experiencing may be due to insufficient systems memory, or perhaps insufficient video memory. The reason I'm suggesting this is because I have a very old Intel CPU in my system (6-core) 5820K and I'm pretty sure some of the CPU pins are bent because I only see 50-75% of the physical memory that's actually inside the system--and even with that, I never experience any of the problems you described. FWIW, I also upgraded my graphics card to an RTX 3090 with 24Gb of VRAM, when they were clearing out their inventories to make room for the 40x0 series at the end of last year--and I did it predominantly because the GTX 980ti I had been using until then "only" came with 6Gb of VRAM, which was reduced to less than 5Gb by Windows' window manager and was responsible for frequent hiccups and crashes involving 3D software.