IMHO it’s worth getting into games because they are a mainstream form of entertainment these days (just like movies) and there are incredibly well made games and all sorts of genres, so that everyone can find something. It’s also a fun hobby, at least as long as you play either with friends, or singleplayer, or a multiplayer game with a non-toxic community. Stay away from popular e-sports titles, they’re usually filled with toxic teenagers.
If you like puzzle games, there are some great ones, for example Portal 1+2 or The Talos Principle 1+2 are probably the most polished ones out there, these are AAA games made by big studios, who don’t usually do puzzle games as they’re somewhat niche but there are some exceptions thankfully. Portal 2 is the highest ranked game of all time on Steam (I think it’s deserved).
There are also tons of great indie puzzle games out there, of course.
Somewhat related to puzzle games are “point and click” adventure games. That genre was very popular in the 80s and 90s, now it’s also rather niche, but still some great ones are being developed all the time. Adventure games are (also) about story-telling and solving many puzzles to advance in the game. You usually find lots of items in those and have to combine them in various ways and interact with the game world and its characters to solve puzzles and advance the story. That’s maybe the key difference between those and more focussed puzzle games where it’s more about the puzzles, less about item combinations and character dialogs. But adventures can also contain quite challenging puzzles none the less.
Genres are hard to distinguish these days because so many games are a blend of different genres. Anyway, you probably want to stay away from games tagged with “action” or “e-sports” and primarily look for “adventure”, “puzzle” or “casual” tags.
It depends. It’s viable if you just need a phone with several open source applications (non-Android) and are fine with that. But if you need Android app compatibility it’s probably going to be harder or more inconvenient to do, though I haven’t checked the status in recent time. And then there’s this evil thing called Google Play Integrity (essentially DRM restricting which apps can run on which OS) which is a problem even for non-proprietary Androids, so you probably won’t have any chance if you’re dependent on such an app (thankfully it’s rare but as we all know stupid ideas tend to become annoyingly popular).
Main problem, as usual, is that Android and iOS have become such big and popular “platforms” for mobile apps that establishing a “third” platform for app developers is basically impossible (also remember what happened to Windows Phone OS, they were late to the market and failed spectacularly to catch up. Of course in this case it’s open source so it can grow regardless of user numbers, but still, it’s hard to catch up when lots of great Android apps were already developed specifically for Android). So you can only hope that Android app compatibility grows mature enough to be close to 100% compatible, so that you can also run almost all Android apps on your mainline Linux mobile OS. Then you’re not “limited” anymore. (At least if you consider it “limited” when you can’t run Android apps. Which most probably consider to be “limited”).
So I think it’s less about the hardware and OS/UI (I think they work fine these days) and more about the available apps.
[My main daily driver phone is a GrapheneOS (Android) and I have a Pinephone with Linux for playing around in WiFi at home only]