Idk, I've run mint for a decade or more. Until the last couple of years all of my machines have had nvidia gpus. I never had an issue with drivers.

So, yes, you are more likely to run into issues if you have an nvidia gpu but it's still pretty unlikely

Is it possible that the driver that was installed was at some point so old that it was removed from the repos?

I can't speak about the exact implementation on Ubuntu, but on Fedora (which I am using) the driver usually gets updated to the latest version automatically. If that's not the case on Ubuntu or Mint, it may be worth going to the device drivers menu every few months, checking if there's a new one available and selecting the new one if there is one.

At their heart, most distros are approximately "made of the same stuff". There's differences in package management in the background (e.g. how the "software centre" works), but essentially the difference between a "gaming distro", "normal distro" and "creative distro" is just what programs are installed by default, and how a few things are set up by default.

Nothing stops me playing games on Mint (and historically, Ubuntu and Ubuntu Studio) - and likewise, nothing will stop you installing office programs, audio/video/graphics programs etc on something presented as a gaming distro.

That depends on what that other stuff is. Bazzite is a desktop OS first, gaming second. But it us atomic, so installing apps that aren't available as a flatpak is somewhat more complicated.

Mint is a great start though, I seriously doubt that you will have problems. Just don't be afraid to experiment.

No you can pretty much do everything the same. The biggest difference is the distro it's based on, bazzite is based on fedora, you use "sudo rpm-ostree install" to install packages. Fedora has a system where it layers packages onto an ostree so if you have an issue you can boot from an old one.

Rpm is only needed for system packages, most packages can just be installed via a flatpack in the package store, which is all free and open source software.

Bazzite is a great starting point. It is pretty much turn key, while having the best performance and proprietary drivers. It already has everything installed to get emulating windows apps working easily out of the box. Wine, proton, steam, the proprietary drivers. These are all things you are going to want probably and this will save you a headache and several days of trying to get the system setup.

Make sure you disable UEFI and choose legacy boot in your bios if it's available and also disable the TPM in the bios if available. It will work with those enabled, but it's buggier and the TPM causes performance issues. Linux doesn't need these and they are artificially imposed by Microsoft and the big corporate OSes, but they suck compared to the original simple standards for bootstrapping. I'm not 100% sure how well this works on everything. It's possible some newer cards might require UEFI boot, but you can just turn it back on before you install.

I recommend KDE as the desktop environment, especially if you are used to windows. It will feel the most natural and familiar to you. I also recommend asking chatGPT to help you with basic tasks like installing system level software. Make sure you specify that you are using bazzite. Once you learn to use Linux its so much better than Windows. The performance is much better in nearly every regard. You can do anything you want with Linux, where windows is extremely locked down nowadays. It also prolongs the life of your hardware, especially drives, since windows spyware isn't constantly scanning your files and stuff. With proton you will likely see a 5-15% performance jump over gaming on windows natively. The downside is that many popular games won't work in multiplayer because of the anti heat, and also some trash software like Photoshop won't work, but the vast majority of windows apps will work just fine, even multiplayer. The developers have to go out of their way to make multiplayer games not work on Linux, so it's pretty rare, even if many of the bigger studios do it. You can dual boot windows for this if you really want to, but windows will constantly try to screw up your boot and stuff so you have to be careful. I would say just not support those companies which go out of their way to not support Linux. They are anticompetitive and anti consumer.

The learning curve for Linux isn't quite a cliff now, it's still steep, but with bazzite it's much easier then it ever has been. It mostly just works from a simple gui install, and there isn't really anything you need outside of this base install. Perhaps you want to install, protonup-qt so you can install proton GE, which has better support for some games that rely heavily on .net code, like space engineers.

It depends on the distro. Bazzite might get in the way since it's a more closed distro if you want to do docker stuff. I personally managed but setting up extra hard drives that docker (podman) uses, but it was tricky. You'll not have issue browsing the Web or installing most apps though.

Nobara might be a good choice although the user base is not that big so you might have to migrate in a couple of years.

Otherwise I'd stick to regular distros since they have great support and will stick around for a long time such as Fedora or Kubuntu. I've also heard Endavour is really good these days.

You should consider choosing a distro based on the Wayland integration since you can get HDR fractional scaling and variable refresh rate with them.