I started with Mint, but for Windows users I'd advise openSUSE too.

There's an issue, though, with them preparing for the next big release to become something like Fedora Silverblue or I don't remember. But for now it's a distribution with the corporate feeling in a good sense as strong as with Windows, almost none of that feeling in a bad sense, and it's very polished.

I went through quite a few distros to find one that would cooperate with my laptop and opensuse is the one that did it.

I found endeavour (arch) to be a much simpler experience vs fedora or opensuse or void. Tpm chip worked right away, clear instructions for setting up secureboot with a hook that signs everything as it's updated, etc. I could barely get void to boot, opensuse worked well but after a power outage the tpm stopped working and I was never able to get it back, fedora I had no success with tpm. I'm sure that's all pretty variable depending on hardware.

If you aren't looking for full functionality of your hardware most any distro should be fine, but...why sacrifice security?

If you're still using Ubuntu, I'm not sure what you're expecting

There is more than one distro.

Is it fair to say that any game that runs on the Steam runs on Steam Linux?

No, it's not that far along. A lot works, but if there's invasive DRM or anticheat then it probably won't. If you have specific games you want to play in mind check out https://www.protondb.com/

I know the variations have gotten better over the years but haven’t done too much research into it.

If you're curious you can just create a live USB stick to test drive it. Won't work well for gaming though.

Did you mean to say "any game that runs on the Steam Deck runs on Steam Linux?"

If so, the answer is yes. It's honestly surprising these days to run across a steam title that doesn't run in linux (though always look into the anti-cheat situation for online games).