Why does an open mail window not come up when you click on Mail

what you are experiencing is not normal behaviour. when i have mail open with, say, safari opened in front of it, and click the mail icon in the dock, it pops up to the front. if the mail window is closed with mail being open or fully quit, it also comes to the front. i'm think you should download and run the free version of EtreCheck so we can see if you have some software that is causing your issue. make sure you give "full disk access" to etrecheck. read how to use it by reading Using EtreCheck. you can see how to post the report here by reading How to use the Add Text Feature When Posting Large Amounts of Text, i.e. an Etrecheck Report. and it automatically obscures sensitive things (like serial numbers) so you don't have to worry about sharing the report here.

you're welcome. :)