I have an old Mac Pro that has been collecting dust for years. Today I bought an SSD and install Debian on the machine. It works flawlessly.
Further reading revealed that there is an active community around the classic mac pros and thanks to their modular nature they can be fully upgraded. People even upgrade the CPUs in this thing.
So if you like playing around with a PC like the old days, that is also Linux compatible, a Mac Pro 5,1 seems a good choice. AFAIK you can get it for cheap and a decent upgrade won’t break the bank.
You’re making me thing: can we still do that (change the OS to Windows or Linux) with the new Apple silicon Macs?
The Asahi Linux project provides a Fedora-based experience for people using Apple Silicon. It works well for the most part but there are features that are still being developed.
As for Windows, I don’t know of any methods to get Windows running outside of macOS, but many people utilize Parallels for Windows apps or the desktop experience.