Still, sorry to hear the experience. I'd have been frustrated too.
For the brightness, hard to say what's wrong without more details. But I hope someone pointed you towards xrandr, which would allow you to manually set the brightness and help determine if it was just a bad setting (edit to /sys/). But could be a kernel issue too. Which sounds a lot scarier than it actually is.
I'll admit, fractional scaling sucks every time I've used it. There are some settings that can help, like letting applications control their setting instead of system. But I don't have enough experience with this, but can confirm it can be frustrating. (xrandr can help here too btw)
The booting is super weird. But that's also something I would have definitely been able to help with. It can seem like black magic at first but it eventually makes sense. Just most people don't bother learning because it usually isn't an issue (my friend and I had a dumb competition to get the fastest boot... We each got under 3s cold and under 2s warm. It was silly, but learned a lot)
Re Steam: I haven't had to do this in a while, but sometimes changing the proton version can make a world of difference. I haven't tried those games though so I can't speak from direct experience.
I will say, I'm not a fan of Mint. I do think Pop and Endeavour are better entry ways. So if you ever try it again, I'd recommend one of those. I'll also say that laptops tend to be a bit more finicky than desktops, especially around display issues. Things are worlds better than they used to be but it is definitely an uphill battle. Lots of variance and not enough resources dedicated to tackling the problems. Hopefully the continued momentum makes this completely a thing of the past. (Battery issues are also a common issue with laptops. In particular putting mobile GPUs into their hibernate state. NVIDIA hasn't been the kindest here...)
As a "not linux expert" I think distribution selection is... a pain point.
It's a bit like the Fediverse. I'm quite happy now, on Hachyderm.io, but it took some trial and error, and the median social media user is ill prepared to go out, select a Fediverse home, and begin piecing things together.
But back to Linux. It's hard to know which distribution, and why you'd select it, when you don't know about Linux. Coming from Windows, it was "Home" or "Pro" (once upon a time). Linux is... though you might not know it, Debian or Fedora, and then a dozen or two varieties off those branches, and then the Window Manager, and then the desktop.
I know nothing about Endeavour, but I've heard of Pop, and I thought it was a thin layer on top of Ubuntu? Not sure why Mint is so different? It's Ubuntu-based too? This adventure actually started with Nobara, which is "marketed" if there is such a thing, as being good for gaming. But I actually had no good experiences with it at all. And did some research and Mint seemed very friendly (and largely was!) But I didn't like Cinnamon much. Anyway, my point is... distribution can have a huge impact on overall experience, but it's very hard to decide on distribution without knowing a lot more about Linux. That pre-education is much more investment than most Windows users would want to make.
EDIT: Oof, I found EndeavorOS on Kagi and... the home page loads, and it says "Mercury Neo with Linux 6.13.7 and Arch mirror ranking bug fix"
I know a few of those words. What am I looking at? I think Linux needs a marketing team!
Yeah distros can be confusing. For the most part it isn't too big of a deal and the main difference is the package manager. apt and dpkg for distros based on Debian (includes Ubuntu), dnf for RedHat (Fedora, CentOS, etc), and pacman for Arch. There's more but you'd run into these the most. I'll be honest, it mostly doesn't matter and it is nerdy quibbling. That said, I still think PopOS is probably the best to start out on because it has some focus around making NVIDIA drivers work. They also build their own laptops (System76) so have some extra experience there. Endeavour is good, but it is Arch based so "rolling-release", meaning you're essentially always using beta software. Mostly not a problem but can lead to some additional instability. I wouldn't expect any real issues, but should be clear.
> "Mercury Neo with Linux 6.13.7 and Arch mirror ranking bug fix"
Yeah... that is weird to put at the top. It's a link to a new blog post. Mercury is their codename, the 6.13.7 is the Linux kernel, Arch mirror being where packages are hosted, and just prioritizing bug fixes. You can read the article if you want. Better would be looking at their about[0] or scroll down further on the front page past the mirrors. IDK why they don't put these things at the top. Definitely a mistake. Pop definitely does this better[1]
For the brightness, hard to say what's wrong without more details. But I hope someone pointed you towards xrandr, which would allow you to manually set the brightness and help determine if it was just a bad setting (edit to /sys/). But could be a kernel issue too. Which sounds a lot scarier than it actually is.
I'll admit, fractional scaling sucks every time I've used it. There are some settings that can help, like letting applications control their setting instead of system. But I don't have enough experience with this, but can confirm it can be frustrating. (xrandr can help here too btw)
The booting is super weird. But that's also something I would have definitely been able to help with. It can seem like black magic at first but it eventually makes sense. Just most people don't bother learning because it usually isn't an issue (my friend and I had a dumb competition to get the fastest boot... We each got under 3s cold and under 2s warm. It was silly, but learned a lot)
Re Steam: I haven't had to do this in a while, but sometimes changing the proton version can make a world of difference. I haven't tried those games though so I can't speak from direct experience.
I will say, I'm not a fan of Mint. I do think Pop and Endeavour are better entry ways. So if you ever try it again, I'd recommend one of those. I'll also say that laptops tend to be a bit more finicky than desktops, especially around display issues. Things are worlds better than they used to be but it is definitely an uphill battle. Lots of variance and not enough resources dedicated to tackling the problems. Hopefully the continued momentum makes this completely a thing of the past. (Battery issues are also a common issue with laptops. In particular putting mobile GPUs into their hibernate state. NVIDIA hasn't been the kindest here...)