I docker’d all of my systems a few years ago, and I’m so glad I did. So much easier to manage, and when I lost a system I was able to get most of my services back up and running with minimal configuration on a VM same day.

As for hardware, you might check and see if you’ve got a local reseller of retired business equipment. Before I moved, I had a place I went to from my work that accepted shit we were getting rid of that disposed of stuff and resold at a bargin the stuff that was still good. I got more than one hp tower from a few years previous that ran (and still runs) like a champ. Felt like night and day when I upgraded to that from my Pi setup.