Again: I do appreciate your input, but what you are saying can be applied to any software - it is not specific to Affinity.
I know how to build a powerful machine, with no "weak links". However, this is not when I built a PC to run Windows 95, when I had basically one or two options regarding CPUs and graphic cards were "Windows Accelerators". :-)
We now can opt to buy a CPU with more cores but with less frequency (or vice-versa); we can spend as as little as 50€ or as much as 1,000€ on graphics; and we choose from 8, 16, 32 or even 64 (or more...) GB of RAM. So, as much as I can appreciate some generic tips, I'm here to get some (much more) specific advice.
I just wished someone from Serif could jump into this thread - even if only to confirm what you are saying (which is, "we did not optimize our software for anything in particular, so just go crazy because more is always better")...