Just to add to that, I have been using the built-in AntiVir for years and years.
It’s only since lockdown that I have more and more online banking and shopping that I thought I’d get a commercial and strong AntiVir program.
I bought Kaspersky (cheap on Amazon) and ran a full and in-depth test. Result: nothing at all infecting the PC, Windows had blocked everything. So no need for a third party application, unless you want keylogging protection and secure keyboard etc.
As a final point, I have not noticed any “hit” on performance.