I always recommend Linux Mint Debian edition. I don't use it, but I've had friends who've had good luck with it. Straight Debian is a great choice as well. If packages aren't new enough, you can always use testing and keep a really stable experience.

It honestly doesn't matter much which you pick unless you're using the absolute latest hardware or something. I personally use OpenSUSE Tumbleweed, which has worked really well for me. I don't recommend it because there just isn't as much help available online specific to the OS, so I tend to recommend more mainstream distros. I used Arch for a few years before I switched, and Tumbleweed feels pretty much the same, but with less fiddling.

Anyway, regardless of what you pick, feel free to come back and ask questions. Most problems have similar solutions regardless of distro because Linux is Linux, so please don't hesitate to ask.

Personally, I really like Garuda Linux and CachyOS for Gaming. You can also check out ChimeraOS or uBlue Bazzite if you want something closer to the Steam Deck.

Linux Mint Debian Edition and Fedora are some general recommendations of mine. Nobara is a fork of Fedora optimized for Gaming.

Go with nobara.

I second Nobara, but IMO get the KDE edition of it if you're used to Windows. You'll feel much more at home.

I have EndeavourOS, but with the nature of Bleeding Edge packages, things can break, so setup automatic snapshots with btrfs (you want this for your data anyways).

Bleeding Edge packages have the advantage of you getting the latest features, patches and improvements, which is required for some gaming cases.

That valve uses Arch is irrelevant in all honesty. Proton is not a Valve product, Valve is merely one of its users and contributors, and it is not wedded to one distro..Similarly Valves own Steam packages are not distro specifi, and there are other gaming platforms to consider which also benefit from Proton (for example you can get Gog windows games working in Linux too quite easily), as well as all the Retro gaming options.

Pick a distro you personally like. I use Mint as I like the cinnamon desktop interface and the distro is pretty much good to go from fresh install. I use Mint both as a dual install with Windows on my PC and also within VMs in Windows. I still spend a lot of time using Windows because of specific games compatibility and work related apps.

EndeavourOS seems a good choice if you do want to go the Arch route but it's only something I've played with in a VM.

If you want something gaming specific then Draugar seems like a good choice - it apparently uses Ubuntu LTS but with the mainline Kernel updates optimised for gaming. But I have no personal experience with the distro.

I also see a lot of people seem to like Pop!_OS, but again no personal experience.

I've had no issues with Mint on my setup.

There is no such thing as a "gaming distro" -- all GNU/Linux distros are equally good for gaming and any other task.

I use tumbleweed, but I had a strange issue with the flatpak version of heroic launcher. I ran a benchmark of cyberpunk 2077 with the flatpak heroic, and was averaging 100 fps. I had nixos installed on a separate hard drive and that benchmark was 160 fps. I thought there was an issue with opensuse, but I installed the flatpak version of heroic on nixos and also got 100 fps. So I installed the regular version on tumbleweed and have 160 fps. I would keep that in mind when looking at programs to launch games, whether it's wine, bottles, heroic, lutris, etc

I use Debian with steam installed via flatpak

Fedora. Cutting edge but works out of box. Very little change in use compared to Ubuntu.

Debian is good but very stable so no guarantee for some package updates which is useful for gaming and maybe proton.

On a related note, this is pretty useful: https://davidotek.github.io/protonup-qt/

Anyone that has video drivers and flatpak should work in your case. If you dislike Ubuntu and don't like the direction, usually poops and mint are the ones recommended.

Garuda is amazing

Not much a of a definitive answer here imo. There's a lot of distros that fit this criteria, but I would definitely stay away from Debian due to the age of the packages. As said, you don't have to go with a rolling distro but at least look for those who keep at least their gaming related packages fairly updated.

The tough part about Arch & similar rolling distros is that they can and will break when you update something, and then you have to know how to fix it. I used Manjaro & EndeavourOS for quite a while. Manjaro was actually stable for me, but when I wanted to reinstall after a couple years to switch to btrfs I thought I try EndeavourOS, due to the criticism towards Manjaro. Unfortunately it didn't even took a year for it to break and now I'm on Nobara, which is okay but also has many issues that annoy me. OpenSUSE Tumbleweed is another often mentioned one, which is rolling but with a delay too, but when I tried it out (before installing Nobara) it was extremely hard to install as the installer was buggy and when it finally was installed it was extremely broken to the point where I couldn't even change my resolution properly.