What mini PCs do you like, and which cooling system have you found nice to have?
The mini-PCs are vulnerable to graphics errors in some video games that can perma-brick them. Many people ran into this issue with Starfield and one specific multi-beam gun turning their mini-PC into a paper-weight.
For cooling I get a desktop sized HEPA filter unit and remove the panel on the mini-pc that permits access to memory/nvme. Enough air will get past the memory/storage sockets to cool the CPU.