This is a solid guide to help people who are not familiar with all the tools we use. I have some suggestions for you to perhaps improve (these are small details that, in my case, have been helpful to me):

1. You say this about compatibility layers: “Expect a minor performance hit as a result of running them through a compatibility layer.” According to what I’ve read about and experienced, using compatibility layers such as Wine and Proton can give you a wide variety of results, depending on the game. Sometimes you get a performance boost. Sometimes you get the same performance. If the compatibility layer is missing something the game might need - like a specific dll file - you can have a performance issue. Anyway, the benefit of using a compatibility layer over an emulator is that yes, indeed, sometimes the software works better in the compatibility layer.
2. Maybe make people a little less fearful of using Proton in Heroic Games Launcher? I would recommend, based on my experience, to give Proton a try before using a Wine prefix. I’ve had so much success with Proton in Heroic Games Launcher, especially using the Proton Experimental branch. You can always try Proton and see what happens (the Proton DB has user experiences from using Heroic Games Launcher, not just Steam). If it sucks, you can try something else. Also, there are ways to use Proton in Lutris and Bottles. There are plenty of instructions out there on how to do it. It’s actually very helpful to have this option. My point: make it clear to people that they have options. There is more than one way to make a Windows game work which is a good thing. Different Wine versions, different Proton versions, different ways to set them up for each individual game. If one way doesn’t get you the desired results, you can try a different method. There’s always hope and there are plenty of people online that might be able to help you if you can’t get something to work.
3. There are distros designed for gaming that come with lots of stuff already packaged with the installation. These include Garuda and Nobara. I’ve recently switched from Fedora to Nobara (which is essentially Fedora with modifications) and I’m very happy. I honestly believe these distros are very friendly to gamers who are not too familiar with Linux. For example, when I installed Nobara, there was nothing for me to do after. No installing launchers, etc. I did have to enable Proton on Steam, but that was about it. It’s really amazing how user-friendly Linux has become in some distros. Anyway, I also enjoy Arch Linux and I like having control over everything, doing things myself. Maybe you could change your text to explain that there are different distros to make a variety of people happy? If you like to tinker a lot, you can choose Arch. If you want an “out of the box” approach you can use a distro targeted at gamers. Maybe you’d prefer something in between, like Fedora, which needs some tinkering after installation.
4. Maybe add something about Steam and its offerings of native Linux games. People would be surprised if they payed more attention. Quite a few games that people usually play on their Windows machines are also available for Linux, which means those games don’t need Proton at all to run. You could get lucky, do you know what I mean? If your Steam library already has games in it for which there’s a native Linux version, you can assess whether or not you need a dual boot system at all. I’m one of the lucky ones. I no longer need to run Windows (recent development, I’m so happy). All my games work in a Linux environment now. It feels friggin’ great to get rid of Windows completely.

Anyway, sorry for the huge comment. Although I’m making suggestions for improvement, please know that my comment is this long because I’m very enthusiastic about your guide. A nice overview of everything a gamer needs to learn about is all there in your guide and this is something that people need if they’re migrating from Windows. You are very generous in taking the time to write this and I’m sure you’re going to help a lot of people who feel lost or don’t know where to start. Great job and thank you!

Yes, your library can be the start screen when it opens. But first you must see the other window (that I always close without reading) telling you about today’s “special deal” or some game you might like to buy.

I’m permanently annoyed with the launcher thing, too. I wish someone would come up with a software store app that 1) installed all the right crap so the game works right and 2) didn’t require you to open the app to open the game. Steam, for example, lets you install the game with a start menu shortcut, but if you don’t have Steam open, clicking on the start menu shortcut opens Steam first, then Steam launches the friggin’ game. Then there is the Bethesda launcher. Then Blizzard’s Battle.net launcher. There’s an Xbox launcher. Yadda yadda. I don’t know if their primary goal is monopoly as much as it is forcing you to open a program with a store in it so you see stuff to buy when you want to play a game. I think having a monopoly is secondary. Primary to them is forcing you to see that they have more shit for you to buy. I’m pretty sure Apple’s iTunes is the one that started it all. Let’s integrate shopping for music into the computer. Then, the phone. Now it’s not just music. It’s every friggin’ thing. People with shopping addictions must have a hard time if they’re also gamers or fans of other digital media.