The customization in settings is extremely limited.

Give KDE Plasma a try. Sometimes they're criticised for having too many settings.

My first foray into Linux was Mint. I'm glad I did, because it's a reasonably friendly entry point, but coming from macOS, Cinnamon began to feel quite cramped quite quickly. The end result is that my server machine is running Mint, but the other computers I have (with the exception of my M2 Air Macbook), are all running Kubuntu with Plasma.

I'm sure that I should prefer Gnome, because I'm a Mac guy, but I just can't get on with it. So Plasma it is.

Proprietary software not working isn't a bug, though. It's by (their) design. The people selling it choose not to make it work.

Can you give some examples of basic features that weren't working with your dual monitor setup?

KDE might also help with this btw, as while I didn't have any glaring issues with dual monitors in cinnamon (on Fedora), it improved overall when I switched to KDE. Used to have to change the audio output to my TV whenever I enabled it, now it happens automatically (plus the option to disable my HDMI audio if I preferred the "keep the same audio when switching to a different video output" behavior).

Only issue was that it didn't work correctly the very first time, followed by it suddenly working the next time when I was intending to troubleshoot it.

Imo, KDE handles dual monitors better than windows even, especially if your secondary monitor is a TV you enable and disable depending on what you're doing. Two clicks to toggle it, it handles different scaling seemlessly across the monitors (iirc, windows would "pop" to the scaling setting of whatever monitor they were mostly showing on as you moved them). Mouse cursor visibility improves when shaking the mouse, so it's easy to find it on a giant screen.

There's a learning curve to it. I have yet to find anything I could do on windows that I can't do on Linux. Lots of stuff took me a while to understand, but daily driving arch for 2 years and I actually cant believe how limited windows is and how I put up with it for so long.

Only real exceptions thus far are that you can't play league of legends or fortnite. And thats because the developers have their servers set to kick any Linux users basically. Not a limitation of the operating system.

That was exactly my experience giving Linux a try for the first time. I gave up but then decided to give it another try with Linux Mint. I've been using it for over a year now and I haven't looked back. There is a small amount of software that I just can't get to work on Linux so I have dual boot set up, but I found myself booting into windows fewer and fewer times. And now I'm at a point where I actually dread booting into windows. I't just doesn't feel like it's my machine anymore when it's running windows.

Long story short, give it time, try a few distros and you will eventually get used to it, at which point you will not want to go back to windows.