In response to your header: Play games with it. :P
I wouldn't recommend Bluetooth as a first choice for connectivity, is there any reason you don't want to use the included wireless adapter?
As for games, I have no idea what you like/don't like. How potato of a PC are you using? FWIW some lower spec games I've played in the past several years with a controller included Cat Quest I and II, as well as the two South Park RPGs. There are also some fun co-op games like Overcooked, Moving Out and Unrailed. Overcooked really spawned a bunch of frantic co-op games that are low-spec and controller-friendly, so you can check that genre out as wlel.
Ryzen 3700X, however I suggest to not worry about bottlenecking; even if does, it's likely to give you the most FPS per $ spent on upgrading. I ran on a i7 920 for the longest time (including the GTX 1070).
Yea, think Komodo is working with Edion for in-store sales. Saw an announcement somewhere when I was reading about Steam Deck sales in Asia (which sadly, just three countries in East Asia).
Also, I went from a 1070 to a 6700 XT myself, can say it doubled framerates in games that needed it (Elite: Dangerous in planetside areas for example), so that's something for you to consider; if you're getting 30 FPS then it'll be a good upgrade, if you're only get 10 FPS it might not be enough.
Think Valve only recently partnered with a distributor for East Asia, so the Steam Decks are slowly showing up in Japan and South Korea. Asus of course has a good distribution network, so generally where they're strong you'll see Allys. I still can't get a Steam Deck in a store, but can get an Ally (and probably the Legion Go).
Yea, some kind of custom install would be good. Can't be hard to program a dialogue before download that'll select the right assets to install, saving both disk space and bandwidth.
The sentiment isn't wrong. Space is cheap now. Had Star field come out when SSDs were having GPU-like pricing I'd be more outraged, but prices are falling and having multi-terabyte systems shouldn't be an issue. Way cheaper than GPUs that can play the game, that's for sure.