I have made a pizzeria imyself in TPRR and here are some suggestions:
1. Have the pizzeria be separate from the actual exterior. Mainly because if you make the exterior too small or too big the interior won’t really look as nice.
2. Try to keep the tables even when building the dining area. Mainly cause it will kinda look weird if a table is out of place.
3. You can try and add more decor around the place so it doesn’t look as bland.
Again these are suggestions. Then again there is coin limit and need to save up on coins but overall this is good work.