So if I get an older version Mac mini...
If you can get the Mac mini for close to free - go for it. But consider it a learning experience and an interim media player. Why?
What OS version does the 2011 Mac Mini run? Apple stopped all security updates for macOS 10.13 High Sierra in the fall of 2020. Roon now needs an internet connection to work so you will be running an unsecured computer.
A year ago I had to replace two computers, the C.A.P.S. V2.0 music server was a based on an Intel Pine Trail Mini-ITX with integrated Intel Atom D525 (1.8 GHz) and was built in 2011.
Soon after my Intel i7 2600K tower computer started acting up, it was built in January 2012.
My conclusion was the average life of a computer is 10 years. Macs may last longer, but how much longer?
The HAL MS-6 is an affordable option but it is Windows 10 based. Unfortunately the current MS-6 version may also be a temporary solution,
it does not support Windows 11 and Windows 10 End-of-Life date is in 3 years, Oct. 14, 2025. Of course after that date Windows 10 will still work, but right now everyone is keeping their fingers crossed that Microsoft continues security updates.
Windows 7 End-of-Life was January 14, 2022 and even though millions of people still use the OS there have been zero updates (except for a small emergency update on 2/8/2022) in the last 9 months.