Mildly Infuriating

Not op, but I've been using various flavors of Linux off and on for a couple of years.

First I'll note that in pretty much any flavor you pick should be able to retrieve data off those Windows drives. You'll probably need NTFS support if you want to read from the drives directly, but I'm not 100% certain about the details so do a little searching before taking the plunge. Files generally should work fine. Images saved in any common format (.jpg, .png, etc) will be fine. Game files could be trickier. If you mean the actual files for running the game, you'll either need a dedicated Linux version or run them through a compatibility layer like WINE or Proton (this may take a bit of luck to get working). If you mean things like save files then that all depends on the particular game... you'll need to research moving data across operating systems for each game. For regular computer files, though, it is usually as simple as throwing them on a USB drive and dragging and dropping them.

Given that you want to do some gaming I would be remiss to not mention that, even in the best cases, Linux gaming can still be a little hit-or-miss. This is greatly exaggerated if you have uncommon hardware. For instance, Linux gaming on Intel ARC video cards is pretty rough right now. Sooner or later you will find a game that doesn't work right, and you may not be able to fix it. Such is life.

As for picking a flavor (colloquially called a "distro") that can get a bit complicated. If you just want a jumping-off point without the full breakdown, then Pop!-OS is probably a good starting point. They aim at being a more newbie-friendly distro, and they have a big enough community that you should be able to find help if you get stuck on something.

You should know that when you're installing Linux, you will usually first boot the computer using a USB drive with the distro of your choice. This is called a live environment, and it gives you a chance to test out a distro without making any permanent changes to your computer. Of course, once you actually do install the new OS it will wipe all data from the computer's drive so make sure you're ready.

If you want to get a bit out in the weeds of picking a distro then read on, otherwise you can ignore the rest of the comment. If you choose to take the plunge then good luck, and I hope you enjoy it!

There are two major families of Linux that I think you should consider: Debian-based and Arch-based. There are a lot more than that, but IMO these are the most appropriate for your use case. Of the Debian-based distros, I'd recommend the aforementioned Pop!_OS, Ubuntu, and Mint. Some good Arch-based options are Manjaro, Endeavour, or possibly Garuda.

When in doubt, a Debian-based distro is probably the right choice. Any of the distros above should do the trick, but all are a little different. I already described Pop!, so I won't rehash it. Ubuntu is one of the most popular Linux distros ever. Probably the most popular for home computers. As a result, there is a wealth of forums and other users you can ask for help. If you run into a problem in Ubuntu, someone else has had to deal with the exact same thing and probably made a forum post about it. Linux Mint, in particular with their "Cinnamon" desktop was made to feel a bit like old Windows 7. It's not exactly like Windows (no distro is) but if you're a long-time Windows user then Mint feels strangely comfortable. Like Pop! its userbase is smaller than Ubuntu, but still more than substantial enough to help out with the most common hangups.

Anyone who knows about Arch Linux would probably raise an eyebrow at recommending any form of it to someone new to Linux, but in my defense, most of the development in Linux Gaming is being pushed by Valve right now, and their new SteamOS 3 (which is what the Steam Deck runs by default) is Arch-based. AFAIK SteamOS 3 is not yet available for non-steam deck systems. Valve has stated they intend on releasing it as a fully-fledged distro, and if that ever happens then it will likely become the de facto standard gaming Linux distro. Until then, I suspect that running another Arch-based distro might result in fewer issues while gaming. That said, while the distros I've named are much more user-friendly than vanilla Arch Linux, the Arch family is generally less beginner-friendly than their Debian counterparts. Some quick notes: Manjaro is fairly popular but a bit weird as far as Arch distros go, Endeavour is clean but I'm not super confident in their noob-friendliness, and Garuda has a gorgeous desktop and is probably the most feature complete for gaming but it includes some power-user tools (chaotic-AUR) out of the box that I wouldn't recommend for new users.

On a final note, if you want to learn a lot about how to use a Linux system, and in particular the command line, you could try installing vanilla Arch. This is almost certainly a terrible idea; you'd have to be more than a little masochistic to try it. If you want your computer to just work then steer well clear of this option. Arch has a reputation for being non-user friendly and borderline hostile to newbies for a reason. If you decide to try this don't expect anyone to hold your hand. And don't ask for help on the Arch forums unless you've done everything by the book, to the letter, and you've actually tried everything else first. But making vanilla Arch your first distro would be a pretty chad move.