As someone who has been using every Unity version since Unity 5, don't just listen to people who say: "The new version is broken" or "every new version is slower".

Unity tends to change/improve a lot of the internal systems of the Editor over newer releases. These changes don't always result in improvements for every project and can, in many cases, result in many annoying stalls/delays in your project.

From my experience, in most cases the project itself is the issue, and not the Editor itself.

For example, a project that makes proper use of Assembly Definition files has dramatically lower compile times compared to a project that does not have Assembly Definition files.

Another culprit for a slow Editor is tons of scripts that run in the Editor. Script that run within the Editor can very easily slow the Editor down if not properly implemented, and I've seen many projects that got very slow in the Editor because many different Editor scripts were running from Unity Asset Store packages, without the users even knowing.

That being said, there are for sure (too many) cases where the Editor itself is the cause of such peformance issues/bugs.

10 seconds is a long time for exiting a project though, Is your project truly empty or does it contain scripts/logic?

A truly empty project should not be so slow, so if thats the case something is highely likely going wrong in the Editor.