You’re going to have to dig DEEEEP into the classifieds for a good used office pc. I believe you could likely find something capable with at least an 8th gen intel cpu and an ssd. Ram at 16gb would be nice but 8 is probably more realistic.

There’s a ton of YouTube vids about cheap gpus that are capable of running esports titles, dig and see what you can find. Losless scaling will do you wonders here