Sorry, Windows Defender. I wouldn’t pay for AV on Windows.
Discussion
I would never trust Windows Defender. I saw some really bad shit happening to those PCs which used Defender. BTW "if you don't pay for the product you are the product". It's a cliche but very very true.
Defender is now one of the better EDR platforms on the market. The number of sensors means they have significant more telemetry data to train ML models.
Many organisations are moving aware from Carbon Black / CrowdStrike Falcon etc.
When it comes to trust, I do not use any MS services unless I absolutely have to for work. Strongly recommend moving to Fedora / Ubuntu and dual booting into Windows if you have a specific need (ie, gaming).