Maybe building one yourself might be a good idea. I found someone’s old desktop with an 8th Gen i7, 32gb of ram, mobo and Gtx 1070 gpu on the side of the road while on a road trip. Thing was sitting in the rain and slightly rusted, but when I cleaned off the corrosion, stuffed it full of hdds and set it up with truenas scale it’s been running flawlessly with an uptime of almost a year. Been running like that for about 5 years now with the occasional maintenance.