EDIT: Latest update

This is something so rudimentary that I'm a little embarrassed to ask, but I've also tried looking around online to no avail. One of the hard parts about being a Linux newbie is that the amount of support material out there seems to differ based on distro, DE, and also time, so posts from even a year or two ago can be outdated or inapplicable.

Here's my situation: I'm a newbie Linux user running Pop!_OS 19.10 with the GNOME desktop environment. Occasionally, games I'm playing will hard crash and lock up my system completely, leaving a still image of the game frozen on the screen indefinitely. The system stays there, completely unresponsive to seemingly any inputs. It doesn't happen often, but when it does it's almost always when I'm running a Windows game through Steam's Proton layer. I suspect it also might have something to do with graphics drivers, as I'll at times notice an uptick in frequency after certain updates, though that might just be me finding a suspicious pattern where none exists.

Anyway, what I don't know how to do is gracefully exit or recover from these crashes. No keyboard shortcut seems to work, and I end up having to hold the power button on my computer until it abruptly shuts off. This seems to be the "worse case scenario" for handling it, so if there is a better way I should go about this, I'd love to know about it.

EDIT: I really want to thank everyone for their help so far. My initial question has been answered, and for posterity's sake I'd like to post the solution here, to anyone who is searching around for this same issue and ends up in this thread:

• Use CTRL+ALT+F3/F4/F5/F6 keys to access a terminal, where you can try to kill any offending processes and reboot if needed.
• If that fails, use ALT+SYSRQ+R-E-I-S-U-B.

With that out of the way, I've added more information about the crashes specifically to the thread, primarily here, and some people are helping me out with diagnosing the issue. This thread is now less about the proper way to deal with the crash than it is about trying to identify the cause of the crash and prevent it in the first place.

Today I went to my favorite bakery/cafeteria/restaurant/grocery store (yeah it's one place, but not large enough to be considered a supermarket - IDK the correct terminology in English but you get the gist). It's a nice place if a little pricey. About a month ago, they installed a gate. Next to the gate, there's a huge metal thing with a single red button. When you press the button, it tosses an electronic ticket (that stores every purchase you make in the system) and the gate lets you go through. These are not synchronous, sometimes the gate is unlocked a lot sooner than the ticket is tossed. So today, after I got into the store, an employee had to run towards me to give me my electronic ticket. Okay.

I noticed that, despite the machine having only one very big button, lots of people still need to be instructed by the employee in order to enter, and he's constantly manually handing out the tickets. There is also a gate to leave that slows things down.

In this last month, I went a lot less to this place. That's because, whenever passing by, I used to enter just to check things up, see if there was something new or appetizing. You know, impulse buys. The need to check myself in and out (even when I don't purchase anything) made me quit that habit. I think other people are the same. Besides, what's the good of automation if it requires a human being to make it work correctly? AFAIK, the analog system worked. And we're not in a dangerous part of town where one needs to worry about people putting products in their pockets.

That's why I say: sometimes, there is such a thing as too much technology.

Is there a good smartwatch/simile that monitors sleep and has excellent battery life (measured in weeks not hours)?

I use the Withings (ex-Nokia) Steel HR, but it … kinda sucks. The bluetooth pairings very often lose sleep data, it's very inaccurate, the reporting sucks for non-24s, and the leather bracelet is of very poor quality, keeps breaking.

I really don't care for the fitness/step tracking which, as someone else here put it, thinks typing on a keyboard or eating is a step.

I also briefly tried an Oura (https://ouraring.com/), but I never got it to work and had to send it back.

I also don't care much for any of those "sleep quality" trackers that try to detect if I snore and what not. I can do sleep studies in my own time, I just want to have accurate stats on whether and when I am asleep.

In the 2000s I used to use a service called last.fm (originally called Audioscrobbler) that would track the music I listened to and give me recommendations based on that. It was able to give me some really great personalized suggestions, but that came at the expense of me handing over significant amounts of personal data.

In prioritizing privacy, I feel like I've stepped away from a lot of the big recommendation engines because they're tied to data-hungry companies I am in the process of disengaging with (e.g. Goodreads is owned by Amazon). I can still find stuff I like, but it's often the result of manual searching that turns up popular recommendations that work for me, rather than less well-known or acutely relevant things. last.fm was good at giving me less "obvious" recommendations and would find music I was unlikely to find on my own. I want that, but for all of my media: books, movies, etc.

There's a second concern in that I also feel like I can't trust platforms like Netflix, who seem to prioritize their content over that of other studios. Their recommendations feel weighted in their favor, not mine.

What I want is an impartial recommendation engine that gives me high quality personalized suggestions without a huge privacy cost.¹ Is this a pipe dream, or are there examples of this kind of thing out there?

1. I don't mind handing over some of my specific interest data in order to get good recommendations for myself and help a site's algorithms cater to others, as I get that's how these things work. I just don't like the idea of my interests being even more data for a company that already has thousands of intimate data points on me.