Reading all of this makes me jealous of random stranger's PC's, since I will never be able to afford anything like this.

I have a Dell Optiplex 3010.
CPU: Intel I3-3220
GPU: Intel HD Graphics
RAM: 8GB DDR3
Internal SSD: 256GB SSD [can't remember brand]
External HDD: 4TB SeaGate
External HDD 2: 700GB Toshiba from previous PC
External SSD: Samsung T7 Portable SSD 500GB
OS: Windows 10, want to upgrade to Linux