It turned out it's a HL12 connector from Amazon:https://www.amazon.com/HangTon-Automotive-Waterproof-Industrial-Connector/dp/B07JCNQVGL
Push-pull coupling, brass with chrome plating, but only rated for >500 mating cycles.
Quite expensive with its pricetag of about 20$, but still cheaper than a Lemo. Not comparable to the cheap 1$ aviators from aliexpress pricewise though.
Looks very good on photos and that's pretty much all you need with those fancy custom cable.