Basically just the CPU fan, case, and PSU (if you're lucky). If someone can figure out how to get Doom running on just those 3 things, young people will be able to ascend.
The top of the market sucks but I've been building am4 systems for people for about 400$. 3700x or 5500 is good enough for most people and as long as they don't break their motherboard they can drop in an upgrade.
My fastest pc right now is probably my 5700x3d and 4070 super. So I feel like I have 2 years to find an upgrade.