So the multiplayer doesn't work because of the "playeruid" is just "" (basically null) and when somebody wants to join you with the repack game you or them get kicked out because of contradiction of the "playeruid" value
Ive talked even with the creator Tyler about this issue(while not telling him it was a repack) basically you shoudl be able to change the uid in the clientsettings.json but the game(repack) just refreshes it back to null value
(Tyler proposed to change the value while being disconnected from the internet but the game still refreshes the value)