I have a similiar venue in my game that I put on that library lot. It has a lot, and I mean a lot, to do. Though the choices I made for what activities was more tailored toward the university experience (so it still has a library and research section and every kind of skill building object you could think of). I also put in a kitchen area on the 2nd floor, and a cafe below it.
Don't laugh, but I left as 'library' lot type. :lol: I did that so that "The Braniacs" still meets there.
I use the mod by LittleMsSam's which lets you set a lot trait for "Employees: Professional" and the result is that the bar and cafe that I have on the lot both get actual staff, despite it being library as a lot type. For your desire to have higher quality meals, that mod I mention also lets you hire a "caterer" on any lot type. It wouldn't be a restaurant, but the caterer would pump out the nicer high quality meals that you desire.
Or you could use a buffet table.
I originally did the same thing as you, and tried to set it as a Restaurant lot type, but I wasn't happy with the Braniacs meeting in a library of another world.
