Defender is free and if you get something it can't mitigate then you're better off wiping anyways.

denender will suffice but the best protection is common sense. If for whatever reason you find yourself needing to interact with sus files there are ways to do so safely in a contained environment

Cancel. The paid plans are mostly for business customers or the additional features. Even if you like their product, the core antivirus is the same for free tiers as it is for paid.

As for Windows Defender, it is perfectly fine for the majority of people. It is no longer the hot pile of garbage it once was. If it was me, I'd just switch to WD.

Malwarebytes double-charged my elderly grandmother and then refused to provide the service that she overpaid for because of a non-functional email verification system. Don't use Malwarebytes. Unless you're downloading tons of executables from some questionable source a virus won't randomally appear on your PC and even if it does, Microsoft ~~spyware~~Defender will do the exact same thing any other anti-virus would.

Defender is fine.

My SO is still on Windows, so I just have Malwarebytes installed to run a periodic (free) scan, and run Defender for active protection. We've been doing that pretty much ever since Defender became a thing and haven't had any issues.

As others said, if there's an issue Defender didn't detect, investigate, and if it's actual malware, reinstall. That'll cover you 99% of the time, and the other 1% (rootkits) of the time isn't worth protecting against for the average person.