Around here we have a higher minimum wage than the federally mandated one, and restaurants aren’t allowed to undercut it. (Cost of living here is crazy.)
Restaurants work around this with scams like adding a “living wage surcharge”, “mandatory gratuitites” (wherein the fine print states none of it actually goes to the staff, but you’re more than welcome to add on extra money that does go to the staff), and so on.
This allows restaurants to have lower prices on the menu, and then surprise you at the end with additional fees. Those fees are generally disclosed on the menu, but only in the fine print nobody reads by the disclaimers around eating raw/undercooked food.
Since you’ve already eaten, there’s not much you can really to dispute it – after all, it was right there and you didn’t read it – sucks to be you. Then none of that goes to the staff so you have to add even more to ensure they get something extra for their hard work.
How about just being honest and up-front and make your base prices higher rather than adding more at the end to make it look lower? Or maybe just don’t gouge your customer so much by charging $40 for something that has $5 of ingredients and takes only 10 minutes to prepare.