Talk to your employer about taking on the role on a “fixed term” basis of say 6 months. Tell them honestly why and see what they say. If you’re concerned about the lack in money see if you can take the 9 to 5 and supplement with the odd Sunday shift back on the floor to prop the wages up if that suits you.
Now in fairness we dont know how high end this Sushi place is, if its a place where your paying for the experience its more understandable but It does read a little bit passive agressive.