SadPandan

I disagree, this seems like a bug, it's just maybe not easily reproducible. There is nothing I can set up to make it work, I tried everything. Only then I discovered in the patch notes that 1.20.2 did some changes around networking and took suspicion that it not a problem on my side, but with the latest patches.

@Juliemc - no mods, we've never run the world using mods, only vanilla installation

Me Neither. There must be a bug in the recent patches, because it works flawlessly in version 1.20.1.

I just downgraded the version and now joining local multiplayer works again. Filed a separate MC-267252 for my local multiplayer issue