Linux

I'm a newcomer to Linux (only about a year in), but here's what I've got so far:

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

Mine wasn't at all. Steam has done a lot of work to make this seamless so that more games can be played on the Steam Deck. Check the Proton DB to see what your gamea look like.

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

I have very little experience with this, but probably. Linux users tend to be tinkerers.

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

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

Same answer for both: There's Wine, and a whole bunch of setup scripts that can get even stuff like Adobe Creative Suite working with it. Worst case scenario, there's VirtualBox for the one or two apps you might need to run Windows for. But I find that the open source options, while they might have a learning curve, tend to be substantially better than either of those options.

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

More or less, but you can pick and choose what updates you want to install and when. Most distros have a package manager that'll let you update the kernel, the drivers, the middleware, the desktop environment, all your apps, and even the package manager itself on your schedule, from one interface. You can also just ignore it and never update anything, though I wouldn't recommend that.

How does digital security work on Linux?

Very well. It's much more locked-down by default, for one thing.

Is it more vulnerable due to being open source?

Quite the opposite. Open source projects are well known for being less vulnerable out of the box; Linux in particular is used by huge companies as a lightweight server OS, so it has a lot of highly-paid people committing security fixes back down to the open source project.

Is there integrated antivirus software, or will I have to source that myself?

Antivirus is a bandaid on Windows, provided because the OS was written with certain naive assumptions that let attackers get access they shouldn't have. On Linux, those assumptions were not made. No application can be installed without your root password, for instance; downloaded files can't even be executed without specifically making them executable; and access to edit system files is restricted by a very robust permissions system.

All of that, plus Linux's much lower market share, also means that no malware authors are really wasting their time trying to write Linux malware. The attack vector just isn't worth the extra effort.

So no, there's no integrated antivirus; but for most users in most situations, it's not needed at all.

Are GPU drivers reliable on Linux?

Your mileage may vary significantly, but anecdotally it seems like most architectures from AMD and Nvidia have good support.

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

Maybe, but like with Windows, I assume you have to really go out of your way to do so.

And also, what distro might be best for me?

I've only used Ubuntu and Mint. Mint has so far been the easiest and most user-friendly of the two. It's also regularly touted as the best for newcomers.