I'd look at start 9 if I was buying a complete solution. For budget minded I actually use an old (2011?) Mac mini running Ubuntu. And a 2012 MacBook pro running proxmox. Both of these were about $100 on marketplace. Gotta check to make sure they're easily upgraded. Some maca are not.

Some NUC style machine, Beelink, Minisforum... Or just some older small desktop machine.

Lenovo ThinkCentre Tiny M-series 👌🏻 You have many variants I have a M93p

That happens when you turn bitcoin into Dropbox

RPi500+?

I recently purchased hardware from system76.com. I typically do not do much on the host system and spin up dedicated VMs for stuff like Bitcoin and etc... Pretty easy to move dedicated VMs to their own hardware down the road should that need arise.