Will my ability to play games be significantly affected compared to Windows?

Depends on the games you play. Because of things like DOSBOX and Wine, it is sometimes easier to get DOS and early Windows games running on Linux than it is Windows. Valve’s Proton compatibility layer allows games written for Windows to Just Work^TM on Linux. My diet of nerdy factory building games and indie titles works perfectly well in Linux, my cousin who plays Bethesda and EA games ran into more irritations. The major compatibility barrier is competitive online multiplayer and anti-cheat systems. Many developers intentionally exclude Linux compatibility. The game runs fine, but you’ll get banned for doing it.

Can I mod games as freely and as easily as I do on Windows?

Probably, depends on the game. I didn’t have much of a problem modding Kerbal Space Program or Satisfactory, the communities offered mod managers that worked perfectly well.

If a program has no Linux version, is it unusable, or are there workarounds?

My suggestion would be to go full native if you can. Like, Adobe Photoshop isn’t available on Linux, so instead of trying to make it work, give GIMP or Krita or one of several others a try. Increasingly, things like Slack are Electron apps, which basically run as a glorified web browser, so they’re fairly easy to port to Linux and it’s becoming increasingly typical to upload them to Flathub.

Can Linux run programs that rely on frameworks like .NET or other Windows-specific libraries?

Yes, through a compatibility program called Wine, which I’ve already mentioned. Though again I would recommend going for native applications than trying to use Windows software on Linux.

How do OS updates work in Linux? Is there a “Linux Update” program like what Windows has?

Short answer: Better than Windows does.

Different Linux distros will handle this slightly differently, but generally speaking your system will come with a thing called a package manager. It’s basically an app store but everything in there is free. The package manager handles updates for the OS itself as well as the software you’ve installed, up to and including updating to the next version of the OS if applicable. In fact as I write this, my computer is asking if I want to upgrade to Fedora 42.

It’s also not as onerous as Windows updates; most of the time it’ll update software, you can use the rest of the system while that’s happening, and it’ll finish and it’s fine. Sometimes it’ll say “must restart computer for changes to take effect” but it won’t force or nag you to do that. You can come to a stopping point in your work, then do a normal restart. None of that “Updating your computer 1 of 7…” it just does a normal boot in a normal amount of time.

How does digital security work on Linux? Is it more vulnerable due to being open source? Is there integrated antivirus software, or will I have to source that myself?

Linux has a system of permissions, a bit like how Windows will sometimes ask you to run things as Administrator. Linux has had that concept longer than Windows has, Linux will call it the Root or SuperUser.

Increasingly, sandboxed applications that run essentially in their own virtual machines are being used to limit what an application can access. Flatpak has a system of permissions not unlike Android, where you can say “No this app doesn’t need camera access.”

We get a lot of security from having a package manager we actually use. Linux users aren’t in the habit of downloading random .exes from all over the internet. Software in the repos is vetted and signed. Don’t run code you don’t trust.

Few Linux systems come with built-in antivirus software. Conventional wisdom is it isn’t needed. Antivirus software does exist for Linux, but it’s often to detect Windows malware in server traffic. For an end user desktop it’s not necessary.

Are GPU drivers reliable on Linux?

AMD publishes their drivers directly to the Linux kernel. My 7900GRE Just Works^TM. Nvidia tends to be a bit more of a pain in the neck. Your system will likely come with the open source Nouveau drivers, which will run but possibly not very well, and you’ll need to install proprietary drivers, which…the method you go about doing that varies from system to system.

Now, I had a hell of a time with the hybrid graphics on my laptop, but I think that’s another story.

Oh, yet another story: on my GTX-1080 in my previous computer, I started to have an issue with a new monitor I bought. Turns out the card needed a firmware update or it wouldn’t let the computer boot with a late model DisplayPort monitor attached. Not a driver update, a firmware update. Nvidia does not publish the tool to do that for use in Linux, so I ended up taking the GPU out and borrowing a Windows computer.

Can Linux (in the case of a misconfiguration or serious failure) potentially damage hardware?

I think I could use dd to wear out an NVMe SSD via excessive writing. But basically no. You’re not going to flip a switch in a settings menu and hear a bang from your case.

And also, what distro might be best for me?

I would recommend trying several. A few of my favorites over the years have been Mint Cinnamon, Fedora KDE and Ubuntu Mate.