I used Avast free for years but got fed up with their endless attempts to get you to upgrade to their paid version which became more blatant as time went by. When I got my current laptop I decided to try Windows Defender and so far it's worked fine. I don't miss the endless pop ups urging you to Upgrade Now! XX days left before you're unprotected! every time it updated itself and then when it comes to it, a microscopic option to continue with the free version after you've waded through the anxiety inducing choices when trying to avoid selecting the paid version. I'm sure the rest are just as bad. It's actually a decent antivirus, if not for the harrassment. A major bonus of Windows Defender is that you don't get any of that.
As for the banks, I can't really say, apart from my bank for years trying to push Trusteer on line. When I cracked and tried it several laptops ago it just made everything soooooo slooooooow. I thought it might have been due to something else but no, when I uninstalled it everything went back to normal. Uninstalling it was a drama in itself, with Are you Sure? You could be vulnerable to (pluck any horrible thing from your fevered imagination). It was almost as if I might die if I removed it. I certainly don't want to try it again even though I'm now on Windows 11.
It reminded me of when I had a Windows 98 desktop which came with Norton Antivirus. That was also incredibly slow, and it was pretty difficult to uninstall. The only way that you find out about these things is if you have them installed, and then you can't get rid of them. In the end I took it back to the shop and they did it. I think they had to reformat it and reinstall everything minus the Norton.
So I'm very much of the "if it ain't broke, don't fix it" school of thought now.