Well, Linux is 32 years old; GNU goes back to 1984, and Unix all the way back to 1970! The history of this OS is much older than Linus Torvalds's involvement; he "only" created and maintains the most popular kernel.
But yes, happy birthday to Linux. Many thousands have contributed to making this operating system what it is today and they all have my utmost thanks for it.
If you really want to learn Linux, you can use any (actively maintained desktop) distro to learn just about everything. Beginner friendly just means the default software is enough to do everything a typical user wants to do, in a way that is likely to be intuitive even if they recently switched from Windows or OS X. Installing and configuring something like Arch or Gentoo can be a good way to learn more about how Linux works, and some distros like Debian or Arch are better as a starting point for customization than a beginner distro, due to having less pre-configured cruft to work around. But you aren't limited by using Mint, unless you choose to limit yourself.
Most of what you can do with Debian and Fedora, you can also do with Mint. You can even install KDE on Mint, and configure it however you want. Debian is a bit nicer to customize, though, because it's extremely stable and most of its apps keep their "vanilla" configurations, or at least a configuration unlikely to cause bugs.
I've never played Starfield, but I haven't had issues with Elder Scrolls mods on Proton. If the Nexus Mods app doesn't work, you can just download the individual mods from their website, which I prefer anyway.
Debian's preinstalled software on some desktops is one of my main problems with the distro and one of the reasons I hesitate to recommend it to newbies, so I like the idea behind something like this or SpiralLinux, but I wouldn't use either distro myself, because I find that the more a distro deviates from upstream and adds its own configurations, the harder it is to troubleshoot issues or configure them the way I like.
As for Xebian, I don't see the point of trying to make Debian Sid easier to install. It's a development release, guaranteed to have many bugs, and not really suitable for the average user. If you can't install and "declutter" sid yourself, it's better to be using the latest stable or even testing release.
The idea is probably to make it easier to get a useful configuration out of Debian. SpiralLinux does the same thing.
I know Okular can do at least most of that. Don't think it's available for Mac OS X, though.
Depends on a few factors, AFAIK as a non-lawyer. If the license allows closed-source derivatives (i.e. is permissive rather than copyleft), then anyone can create a closed-source version with all of the contributors' changes, including the original maintainer. And anyone can choose to keep it open-source. The community contributions still to some extent belong to the contributors, though the license waives most of their rights.
Some projects are copyleft, but contributors are required to sign a license agreement (a CLA) which allows a single entity to change the license as they desire, including to closed-source - this is a good reason to avoid such projects. The contributors don't own their work in such a case, but they can still fork the old project as it was before being taken closed source.
In a copyleft (e.g. GPL) project with no CLA, it's illegal for anyone to make a closed-source version, and a major contributor could sue even the maintainer for doing so.
In all such cases, the change to a closed-source model does not erase the existence of the open-source code with community contributions. A fork is always possible.
You mean one that allows logging in and posting to Twitter aka X, without a significant fee? Not to my knowledge. Lately Elon and co. have been working to make third party clients completely impossible to develop, so it's either use the official app, use the website, or quit Twitter.
If you just want to browse Twitter, I don't know of any options for that either, but keep an eye on Nitter; currently it does not work, but they're apparently working on a way to work around Twitter's latest changes.
For the future, it's probably best to post to Lemmy communities from a Lemmy, kbin, or Friendica account; otherwise you risk the formatting of your message getting badly messed up, as it has here. It's cool that you can post here from Mastodon but that doesn't make it a good idea.
It would also have helped if you included some description with your link.
To be honest, I've never used or heard of a keyboard or mouse that doesn't work with Linux. The space is pretty well standardized so generic drivers work for everything. I don't have experience with keyboard layouts that aren't English QWERTY, though. The safest option would be something basic from a major brand, extra stuff like RGB is not 100% guaranteed to work.
I've never used AMD, but folks I know have had good experiences with both; support is about equal. You probably don't need to go for a top-tier device, and if you're running VMs and containers you should be just as concerned about RAM and disk space as CPU