My personal opinion but also based on current industry testing standards
Windows Defender (don't overlook the naturally inbuilt AV! It is excellent in today's standards)
All I would say is I personally tend to avoid AVG, McAfee, Norton etc. purely because from a software perspective they are much more commonly known to cause conflicts. Not to say they always do, just when there are BSOD for example, that are being caused by antivirus software, it's usually those that tend to have the issue, whereas I've never really seen them with others such as Bitdefender.
Kaspersky Free has been working awesomely ....for me....
Poll 30-40 experts, you are quite likely to have 10 very good products listed 2-4 times each...
(testing I've seen of and AVG/Avast products showed both to be fairly competent, but, I'd certainly not pay for either...)
I used Microsoft's included Defender (now relabeled/rebadged as simply MS Security?) with no issues for more than a year, but, as I don't download crap or junk and mysterious sources' patches, video players, or 'free movies', I'd probably have no issues running nothing.
Put a pop-up blocker like U-BLock Origin or Defender extension on your browser as well...