Looking at similar shows to 'Jobless Reincarnation', you gotta bring up 'Made in Abyss'. The world-building isn't just about drawing a big map; it's the rules of the Abyss itself, the curse of ascending, the different layers each with their own ecosystems and ancient tech. It feels like a dark, beautiful puzzle box you're descending into with the characters. The deeper they go, the more the world reveals its cruel, fascinating logic, which reminds me of how 'Mushoku Tensei' slowly unveils its continents and magic systems.
On a different vibe, 'Log Horizon' treats its game world like a functioning society. It's less about the fantasy spectacle and more about the nitty-gritty of how people would actually live, trade, and govern when stuck in an MMO. The politics and economics feel real, which builds a world you can believe exists beyond the main cast's adventures.
I'd throw 'Ascendance of a Bookworm' in the ring too. Its strength is in the granular, almost anthropological detail of how a medieval-ish society works, from papermaking to class structures, all seen through the eyes of someone trying to reinvent modern conveniences. The world feels lived-in because you understand its systems from the ground up, which is a quieter kind of world-building but just as immersive.