Hi Leon,
I can't find the link sorry, but I did read a regular review of antivirus and security options late last year, which put the latest Windows Defender near the top. This link I did post in a previous thread however.
Here's a short version:
https://www.tomsguide.com/us/windows...view-2209.html
I remember reading the other article in shock, as Windows Defender was always considered a half baked toy. It has evolved, and has the luxury of excellent integration into the OS, being "in house".
You could do a lot worse. Updates are handled by Windows update for further simplicity. And to answer your other sensible question: Windows Defender will step aside automatically, if you install something else, and return if you uninstall said AV.
Party on