A few things:
- When switching / upgrading Unity Versions you should delete the Library Folder - the best way to achieve this is to perform a fresh checkout in Git - this will already resolve lot’s of crashes. - This should be done even for minor updates.
- Check that your PC has enough RAM and resources to perform your Unity workloads (depending on the project size a beefier PC can be required than what is stated in the minimum requirements)
- If any crashes occur check the Editor.log to see what was the cause of the crash (it’s quite likely it is a broken editor script either from you or a third-party library causing a crash - if so fix your script or contact the corresponding third-party)
- If the crash is caused by Unity itself, report it to Unity (a popup should appear) and try to attach repro steps
- Unfortunately you are right that there are crash-bugs introduced into LTS version more and more recently. I already triggered a discussion about this, and some people from Unity will discuss a better strategy for keeping future LTS updates more stable, see here: Editor keeps crashing constantly page-2#post-9104989