I would first like to say that I enjoy playing the game despite the small flaws it has. and despite what I might recommend I have NO experience making games, so if these ideas don't work or cant work then I understand. also these ideas might not work with each other either, I'm just spitballing things that (In my opinion) might help you in this game or others you might work on :)
This game is good, and I like the idea. however, I personally think it might work better as an idle-esk game. but that's just my opinion.
The Menu is a little confusing to begin with. maybe it would be smoother if it was split across before service and after service.
(E.g. before/after service chat with the staff. being only able to buy items/food after service.)
A day and week system might be a good idea as well. weekend have more customers, maybe you can throw a party or event on certain days.
Again I have NO experience making games, but I thought i'd share my thoughts because I'm excited to see more from this game and other games like this that are actually worth playing.
Keep up the good work :)