IMO it’s not that Debian isn’t good for gaming. It’s that it’s not good for gaming IF you want to just install Debian and start gaming right away. There’s going to be a bit of downloading/installing, & configuring first.
If Debian is too far back of a starting point for you then I’d either go with a gaming distro where many things will already come installed and possibly (idk for sure because I’ve not used any gaming distros) configured for you to where you mostly just need to sign in and download your games.