It's been a long while since i used a desktop and honestly can't remember what antivirus software i used, and even then, probably the landscape has changed over the years.
Atm i've been winging it with just Windows Defender (no custom configuration) and scanning any thing that looks suspicious on VirusTotal, but probably that would be not enough.
I'm thinking on get a couple of pirated files, so i'd like to be as secure as possible.
You could pirate Eset smart security, but most antiviruses are only like 5-10% more accurate than windows defender, usually at the cost of a lot of RAM and CPU usage, so it might be a lot of hassle for little result.
Nonsense. The first thing I used to install on a newly formatted machine with a cracked version of windows, before windows defender was a thing, was a cracked version of nod32. In fact, I've never paid for an antivirus.