That's definitely a bit on the budget-unfriendly side once you add in RAM and a case(most won't want to go caseless). I'm mainly looking at miniPCs for the build so we can do all new stuff if possible.

I've been messing around with a mostly sufficient $115 miniPC recently(I'll post specs when I get home), I'm kinda hoping to figure out something in between it and needing to resort to used parts to get a decent price. It won't meet that lofty SFV/MK11 goal, but it runs everything I've tested so far without issue, though I have yet to really try and push it. I know it runs Atari 50, Streets of rage 4, etc at full speed 1080p60, but it also falls short of running Pinball FX3. But I also don't know if this is the cheapest we can get away with.

EDIT: This is the MiniPC I've been tinkering with - https://www.amazon.com/dp/B0B3LKG9J6?psc=1&ref=ppx_yo2ov_dt_b_product_details It was $115 when I bought it, but as you can likely see that has gone up.

EDIT2: I just noticed that the link above is NOT to the one I picked up. The one I got is the same as that except it has the J4105 CPU, and this version seems to no longer be offered.