I’m biased towards AMD in general, I just find them to be a slightly better value, but Intel CPUs are great too, and I don’t think they have any noticable issus on Linux.

As for other hardware, it depends. Just make sure to do a bit of research and compare multiple options, especially for something like the storage, motherboard, RAM, or power supply. It’s usually pretty easy to sus out which brands are trying to catch your eye with low prices and tons of RGB, and which brands are offering a great product (I will suggest Seasonic for a power supply. They aren’t the cheapest but the build quality is excellent).

I think you may be out of luck with a built in achievement tracker unfortunately, although I personally haven’t looked into it. I’ve never been a big achievement hunter, but I’m sure there are external Linux compatible tools for tracking such things.

As for recommendations, you’re going to see a million names thrown around. As a broad suggestion, I might start with something based on Debian (tried and true, tons of resources, huge community). Maybe Pop! Or Mint. There are purpose built gaming distros with more tools and optimizations out of the box, however these are often small projects with shorter histories so I’m hesitant to recommend them.

As for desktop environment, it depends on what you want. KDE is my go to. By default it handles very similarly to Windows, but it’s incredibly customizable so you can really set it up however you want. KDE also has basic HDR support, which can’t really be found elsewhere. Gnome is a little more MacOS like, but it’s really its own beast. Gnome is great if you leave it default but I think it sort of falls apart when you try to customize it.

Also, if you do decide to go with Linux, I emplore you to look at getting an AMD graphics card. Their drivers are built into the Linux kernel so they require little to no setup, and usually perform better than NVidia. NVidia cards often have niche, hard to solve issues (speaking from experience. I spent a few years with a GTX1080 and often had the strangest bugs that I just couldn’t solve. Switched to an RX7600XT and everything just works). As a bonus, AMD is also usually cheaper than NVidia.

Fyi an alternative to Playnite with a similar goal is Lutris. You can even integrate several platforms like Steam and GOG to download games directly through the Lutris interface.

On top of that, it’s super easy to install games via exe’s, custom install scripts, add existing install folders, etc. The UI is a little bit spartan compared to Playnite, but it’s very powerful.

I say this because, among other things, a huge benefit of Linux is that it’s great for older hardware. From the sounds of it, you aren’t looking for the latest and greatest in terms of build specs, so Linux may be right up your alley (also no built in spyware, ads, forced online connections, and resource hogging processes that can’t be disabled).