Linux

he is still completely new to this so I want things to work out perfectly for his first experience.

If you're able to be there for the install, then great. I've had a couple of times where, due to certain hardware, it needs a different sound server or some other workaround. In an extreme case, you might need to fallback to a second choice of distro.

but I have been hearing a lot about Bazzite lately and see that it offers a very nice gaming experience

Is there anything specific you've heard that applies to your friend's needs? (Honest question, I haven't looked deep into it.)

If it's just small things like 'Steam and [etc] is installed already', then you can just do that easily anyway.

no typical package management like apt or pacman as I browse their docs, instead it relies heavily on Flatpaks [snip]

Keep in mind that Mint uses apt and (optionally, but IMO inevitably for a gamer/dev) Flatpaks integrated in their package manager, which has gotten much smoother but still is two different systems which can cause confusion. I don't know how Bazzite handles this.

I've been using bazzite for going on 2 years now and it's still as good and as easy to use as it was the day I got it. I wouldn't want to use anything else.

Bazzite 100%. It's the best out of the box gaming distro, and bonus points for immutability (not that your friend needs to know what that is).

Bazzite has newer drivers, ditto for CachyOS Handheld Edition for another SteamOS clone.

If you are afraid of being limited by flatpak for bazzite, (or any other distro but arch), you can use this :

an Arch container using distrobox that can run in every distro.

This way, you'll have access to the AUR and arch repos in general.

He should start with Mint, learn the system in general, and then move to Bazzite, CachyOS, Pika or Nobara, which are more game centric.

Fedora KDE.

Steam and Heroic work fantastic on it.

Has its own App Store for searching for stuff.

Looks similar-esque to Windows so getting around is less painful.

Recommend the one you use yourself so you are able to help them in the best way possible.

Definitely not bazzaite, it has lots of unremovable bloatware and since it doesn't have native package manager it will be a problem. For gaming i propose cachyos, it focuses a lot on performance in games. They have their own proton, kernel and they even had their own browser

In order of ease of use; Nobara (Fedora based), popOS (Mint/Ubuntu based), cachyOS (Arch based, easy enough to use but might be overwhelming because of the amount of linux jargon going on) over bazzite, depending on your friend ability and wish to tinker around with his OS.

I have had problems even dragging dropping files across apps in bazzite and other immutable distros like bluefin. If your friend is interested in tinkering just a little bit then he will be be banging his head across a wall with bazzite. The community support for these relatively new immutable distros is also quite bad when it comes to edge cases.

I'd say Bazzite but I would warn him (and since he's a developer already it might not be a big deal) if he's looking to do any sort of dev work or whatever with Bazzite then prepare to utilize stuff like distrobox, flatpaks, etc to accomplish stuff like that.

That being said as a dev and gamer myself if my first linux experience was Bazzite I might get annoyed. Mint is a great first experience. when I originally tried it well over a year ago though I did have issues with my Nvidia GPU on it and gaming wasn't super great BUT it's been awhile since I've used mint so that may have changed.

Honestly I would suggest start with Mint and just drive it for a couple weeks. If he likes it but feel it's limited for some things then that's when he can expand out to different distros. And like I said maybe gaming on Mint has improved since I last used it. But if he's comfortable with running distrobox and containers then Bazzite is fine.

I built a new gaming computer a month ago. After a couple hours of research, I chose Nobara. It was by far the easiest experience I have ever had setting up an OS and everything has worked flawlessly so far. Even my wife who isn't tech savvy at all has no issues using it. I cannot recommend it enough to new users who want an easy time gaming. I've been a linux user for almost twenty years, but I just wanted something easy that didn't need tinkering and Nobara delivered.

If he's a dev, he probably is able to follow this guide:
https://wiki.archlinux.org/title/Installation_guide

The result is a system, that has virtually every package you can imagine in the aur, always the newest packages - which is quite important for gaming performance and a really slim system.

For the gaming part I recommend Gamescope:
https://wiki.archlinux.org/title/Gamescope

As desktop Plasma is a good choice for beginners. However I personally use Sway.
https://wiki.archlinux.org/title/KDE#Plasma
https://wiki.archlinux.org/title/Sway

Mint for the community support. He'll have tons of resources if he runs into anything and you're not available. As a dev he should be resourceful in that regard.

But definitely check the kinds of games he's playing. Modern multiplayer games will be a big hurdle if they're not steam verified.

I think Bazzite is the "easiest". But I think it would be very difficult to tinker for someone not used to Linux. It's the plug and play option. For me the fact that bazzite tries to be immutable is a very good plus for stability on the long run. And somehow fits well for gaming on Linux. The drawback is that these immutable distro are hard to tinker with if you dont have experience with immutable package managers and so on.

CachyOS has maybe a more traditional structure but should offer good performance too.

There is also Nobara and Pop OS.

I'm on PoPOS but it's too recent for me to give feedback for gaming. But it should work well too.