Best deals at local elections recycling. On a good day, all those are available. May need some work and time to get fully functional, but great learning experience on low budget

Something Epyc

Copper in those heatsinks is worth more than the server

Don’t use car battery in UPS. They are made to start car, high surge current. Under deep cycle in UPS, battery will be ruined in a dozen cycles. Get a 12v 50-100ah LFP (LiFePO4) battery. Wire it to UPS. Should do the job. I retrofitted multiple UPSes with quality LFP. Much better

Typically any server nvme SSD with mlc or enterprise tlc. 960gb / 1.92tb / 3.84tb. 800gb or 1.6tb if really need high write, they can be pricey though

VMware player. Good for beginner in virtualization. Using it on my gamer that slowly morphed into staging server