Don't get too excited, this is pretty boring stuff
The thing is, I actually don't use any antivirus/malware/security software (except firewalls and ad-blockers which I do use). I find they're more trouble than they're worth, they're horrible intrusive hacks similar to the malware they're supposed to protect against, they tend to slow down everything and cause all kinds of compatibility issues. I briefly tried MS Defender when Windows 10 came out and quickly disabled it.
I rely on my own set of security "policies" and frequent + comprehensive backups which have served me well and kept me safe for ~30 years of Windows computing (knocking on wood).
One of these policies is to not let any software handle custom protocols off the browser as this mechanism is easily and commonly hijacked by malware.
I'll admit this is borderline overly-zealous, to borrow Z's words.
In my case it doesn't hinder me, as I like to take a look at the archives' contents and I often rename the archive files (many of them are very poorly named by the MAs) inside my browser's downloads folder, before moving them to MO2's downloads folder. It's easier for me to do all this from Windows Explorer, rather than switching back and forth between MO2 and Explorer. I think MO's Downloads tab interface is very poor and cumbersome to use.
I have an IT background too. I can't stand the babysitting of security software and having to exclude a bunch of apps and folders all the time just to get trivial work done. I know what I'm doing, I don't need this kind of 'protection' - thank you very much.
To anyone else reading this: don't follow my example, it's not helpful. Please use security software.