I went on the Internet, and discovered /r/flashlight. Results:
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The "big" black one is the Wurkkos FC11, basically their "too lazy to do research" #1 recommended everyday carry light. About 12cm long, or the size of a whiteboard marker. Runs off a single 18650 cell, has an integrated USB-C charging port for it, and puts out a solid 1300 lm of light - or about the same as a halogen high beam. Watertight and pretty robust.
The silver one is a Sofirn SC01 keychain light. It's tiiiiny
and runs off a correspondigly tiny, but still standardized and swappable 10180 cell - and amazingly also has an integrated microUSB port for charging. Output is 330 lm - so still ~7x of a typical smartphone LED flash. Also watertight, and the body is stainless steel - should not scratch easily in a pocket with actual keys. Only downside I've found so far - it gets quite hot when running on top brightness, and the on/off switch is by twisting the front part with some force - which is what gets hot. Still, for a keychain light, this is pretty perfect imho.
Most surprising to me is that these two didn't even set me back 50€ in total. There are other popular lights on that subreddit though... for now, I'm good.
For now.