HOW to install a specific version of Unity !?

Folks, I'm at my wit's end with installing Unity on Linux. I need to use specific versions and they're just nowhere to be found. The Download Archive has direct links for Windows and Mac but not for Linux. The [Unity Hub] button does nothing on any version of Linux I've tried and people all over the Web seem to have the same problem.

The What's New page for a given version has lots of downloads for Windows and Mac but no downloads for Linux.

And of course the Unity Hub only offers the latest subversions.

So what am I missing?? How, after offering Linux builds for more than five years, do we not get simple download links?

 

Perhaps this will help: https://forum.unity.com/threads/how-do-i-download-archived-version-of-unity.986448/

 

Or this: https://forum.unity.com/threads/temporary-workaround-for-hub-bug.989477/