I wouldn't recommend Ubuntu as much. It has a bad reputation on forcing users it's own, corporate stuff down their throats.
A great newcomer-distro is Mint. It is very user friendly and just as capable as other distros. Especially as a long-term windows user you may find it familiar and very sanely configured.
Otherwise, Fedora, may it be the "normal" version or it's immutable variant, is also a good choice. But, both are a tiny bit more advanced than Mint. Mint is the king in that regard.
The Gnome desktop is very different than everything you've encountered, you may like or dislike it. There are also other desktops available if you're interested.
I'd say, start with Mint to get everything familiar, and then switch to Fedora Silverblue. SB is my favourite distro, since it's very flexible and ultra-low maintenance :)
and ensuring a smooth gaming setup.
Just install Steam (and maybe Lutris) and you're done. You don't need anything else. Your AMD GPU driver should be pre-installed, or the Nvidia one is easily installable too, usually at the start wizard. Otherwise, you don't need anything else.
All the stuff on "gaming distros" is not needed or individually installable.
Any must-have tools, software, or tweaks?
If you're on Fedora or Ubuntu (Gnome by default) the Extension Manager is great. I'd recommend checking that out and looking for extensions like GS-Connect or so, they're great.
Otherwise, just scroll through the Software Center and see if there's something that exites you. Everything else essential is already installed.
Your insights, recommendations, and personal experiences would be immensely helpful as I embark on this exciting journey. Thanks in advance for your guidance!
Of course, inform yourself first a bit on how to use Linux. Stuff like using the software center to install stuff instead of hunting the web for .exe-equivalents, alternative programs, and so on. Otherwise, if you've already done that, here are a few advices from my side.
If you like your setup, don't change it. If you feel good on Mint, stay on it. Don't distrohop. Most distros are the same.
You could check out Distrobox later in your journey. It allows you to create integrated containers, which is super useful when programming or when a software isn't available for your distro.
Don't overcomplicate everything. Most mainstream or beginner distros are sanely preconfigured, especially Mint and Fedora. They work out of the box.
If you settle on Gnome (especially Fedora), use the default workflow how it is intended.
And don't use "pro" distros like Arch or NixOS at first. They may be good, but not for a starter.