I had a similar experience recently. Updated my Manjaro setup, rebooted, and was greeted with text mode. X just didn't load. 1 hour of reading logfiles and pondering about why the kernel module wouldn't load, it turns out I needed to add an obscure boot parameter (I think it was something like "ibp=off") to my kernel command line to make the nvidia module load again.
Easy solution if you know how to solve it, 1 hour searching for that solution, and about 0% chance of that knowledge ever being useful again in the future.
In the end I was still satisfied because at least I learned something (no matter if it's useful or not), and I was under no pressure to get that particular Linux system working again (I could still dual-boot Windows for example).
I had a similar experience with a workplace machine. It worked flawlessly. But, sometimes, I went to make myself coffee or to the bathroom, and when I was back, the system just never woke up from sleep.
I try setting the machine to sleep and manually waking it up. No problem.
Later, I spent some time watching a long youtube video, then I opened the terminal and then the OS crashed.
Dmesg? It showed nothing
But, sometimes, when I tried to launch the terminal, I tried running htop and then the OS hanged. I had the feeling that it was something HD related.
I restarted the machine, updated the kernel, asked the forums, everything. No answer.
It was my work machine. They let me install Linux but I couldn't spend so much time with the OS. I need to have work done. Otherwise I need to bail and go back to Windows (ugh).
I was about to delete Linux from the laptop, but I had an idea: The machine was a Thinkpad T1. I looked on the Arch Wiki about compatibility with that laptop. If the problem came from an incompatibility with the hardware, it will surely show up there. The machine showed up in a list and according to the wiki, there's nothing related to a crash or a freeze.
Then, I looked up on lshw if there was any piece of hardware that was different of what the Thinkpad has by defaults.
The result? A Kingston 1TB SSD. I googled "Linux Kingston ssd lock up", "Linux Kingston ssd crash".
It turns out, some Kingston SSDs don't support all the deep sleep levels of energy saving. I needed to switch some off with a kernel parameter.
This is one of the benefits of being "obscure in only one area at a time" - just like you shouldn't break more than one law at a time, heh.
Linux is a relatively obscure OS, but you were on popular hardware with a popular SSD which helped increase the chance that someone else had run into a similar issue.
I had this issue after I built my first new machine in nearly 8 years.
I forget what I googled, but I essentially found a forum post almost immediately that explained the reason for the ibp=off, something to do with an intel security issue, caching, and the actual likelyhood of it being a security risk on a personal machine. The conclusion was basically "its enabled by default because its a good idea, but not really needed for most use-cases". Away I went disabling it, somewhat understanding why it was there.
But I've also been an arch user for years, and one thing I'm accustomed to is when the bleeding edge breaks something, other bleeding edge users are already discussing it. The overall community documentation on issues is exhaustive. If you have an obscure issue in Windows and search the error, you get windows support forums with official support asking you to click the "try to fix it pwease" button and no other solution. Half the time the only fix is a reinstall.
I ended up building a new computer because my old machine's windows install got itself in a state where it would fail to login after an update, yet constantly tried to apply that update after I'd revert it. No solutions anywhere online, no way to stop windows from trying to apply the ill-fated update. Just a broken install. I figured if I was going to spend hours re-installing and reconfiguring windows, I might as well get new hardware.
Anymore these days if it only takes me an hour to wade through all the reinstall/switch distro garbage to fix some obscure nonsense problem I count it as a win.
Easy solution if you know how to solve it, 1 hour searching for that solution, and about 0% chance of that knowledge ever being useful again in the future.
In the end I was still satisfied because at least I learned something (no matter if it's useful or not), and I was under no pressure to get that particular Linux system working again (I could still dual-boot Windows for example).