Actually, you don't have this choice anymore.

Apple is disabling downgrading across all of iOS, and starting to do the same with MacOS. So you need to keep old hardware to run older MacOS versions, and it's only a matter of a few years before Tahoe is the latest OS you can run on your Mac.

That's a very temporary solution to be fair. KDE and even, shudder, Gnome put mac os and windows to shame when it comes to responsiveness, performance, and resource usage.

I mean, KDE does 3x the stuff for 1/3 the cost. That's more memory and CPU for your IDE or, more likely, chrome tabs.