Thank you for your time and patience (but you might need more :-) )
First off, this was a new computer and the mail notifications has been as described from first off so system restore surely isn't an option. As I said before I have a Win 10 laptop (LT) and it and this one are using the Edge browser and I've never been near chrome. Both computers are using the same version of Edge. When I got this one, I tried to have everything the same as the Win 10 LT (except loading the mail app with my gmail adress).
As gmail is not in the mail app, when I click "mail" the page is empty. I wouldn't see the gear icon until gmail was in the mail app again.
If you have the patience to continue, I'd prefer to only try one step at a time but isn't it clear that the "problem" lies somewhere with Edge rather than the mail app which doesn't have gmail "loaded"?