Use numerous ones.
I don't use an admin account, often use a VPN, recently I have controlled folder access turned on and application guard (though don't use it often), encrypted drives, different 20bit random passwords for every website etc. I have a drive for Windows, another for games and a third for files.
I got a trojan a few weeks ago that turned Defender off. I couldn't turn it back on in settings regardless if I was admin or not. Got it on again by spending an age in regedit. Ran a scan with all the usual suspects... Defender, AVG, Avast etc. Nothing.
A scanner called Emsisoft found it and two others that must have been on my computer for 10-15 years. The two old ones were definitely dodgy. No misdiagnosis.
Did a full wipe and reinstall.
I was playing WoT today and suffering a frame rate to 35fps regardless of settings (even 800x600). So I went into settings to uninstall the drivers and noticed loads of my privacy settings has been changed. Defender is still on though. I've just run all the usual scanners again and nothing found but i'm convinced there is something on one of my game or files drives but it's undetected.
All this recent stuff since I watched an NBA basketball match (I know I shouldn't have done but I was thinking about following a team for a season and don't know who to spend £100 on... never followed sport before!).
Point is... don't put all your trust in one scanner, or two, or any of them! Use as many as you can imo.
I only browse the internet, do bookkeeping and Office work and play WoT so I'm now weighing up moving all my accounts (business accounts) to a Linux distro and GNU cash and binning off playing WoT.
Security is sooooo big. Look at Marriot. Compromised for 4 years without detection. Half a billion users data taken. I'm convinced MS have been compromised too. Twice I've had an ransom email telling me my hotmail password and i've used windows phone since 2002 until they shut up shop. A short stint with Android and im now back to an ancient Nokia. The passwords sent to me are from when I had the MS phone not the Android one. I've never used Outlook or Thunderbird etc...or at least not in the last 20 years or ever with my hotmail account.