Safari won't open after Big Sur update

I spent 2.5 hrs online chatting to apple support today trying to resolve this issue. Basically on my late 2014 Retina 5K imac since installing Mac OS Big Sur 11.7.10 Safari will no longer open. It doesn't work in safe mode with all other devices removed. A lot of the suggestions online involve checking Safari settings but I can't do this as it won't open at all. In finder it shows as being last opened every time I try but Force Quit never shows it as open. The suggestion was to take it into an apple store but this isn't possible for quite some time for me and it seems as if there should be some way to resolve the issue without that. I thought I'd try to get another browser from the App store but don't see any when I search. Any help would be greatly appreciated :)