I also would like to see a DRM option on itch.io to avoid thinking about selling Steam keys with no build. I would rather sell the build on itch.io, but for all the hard work/money spent on building a game, I would like to have some measure of defense against illegal distribution.
I tend to avoid: Anything that requires activation on Steam and any standalone DRM that requires the game to be activated using the internet.
Basically, I'll only buy DRM-free games and games with serial keys that activate offline (so they're not dependent on a server, the key is checked locally and would work on a computer with no internet access).
Mostly I buy PC games on GOG.com because I know they'll be DRM-free but I shop here for other things but take extra care to make sure what I'm buying is DRM-free or if a serial/CD key is used that it's not an online check.
"Piracy is a service problem" - Gabe Newell
Do consider those words for they are the way in which Steam entered the Russian and Brazilian markets and made absolute fortunes in environments that are extremely piracy-friendly.
I refuse to deal with Denuvo-encumbered games precisely because there are so many alternatives available to play instead.