Most ceilings are not perfectly level that is why you see molding at the ceiling line even when cabinets are taken to close to the ceiling. The lighting should have been all done before tiling but too late to fix the ceiling so either paint the gap like the ceiling and leave it or spend the money on trim no one but you will notice sameas the grout on the accent tile in your other post.

So 1 1/4” over about 15’? First, investigate the corner that's sloping down. It’s probably just normal settling, but Check for subsidence and support issues to be sure. If everything is fine, then definitely hire a drywall artist to float it. Not all drywall guys can float. See their work first.

Move the lights, then the ceiling will have to be furred and re-drywalled. You can float a 1/2", but not the 2" you need.

Hello! I just thought I’d show you all what we ended up doing. We haven’t finished yet but so far, so good. We hired a company to come out and do some ceiling work. They repaired, floated, and painted the ceiling. We already put crown molding over the sink area, and we’ll do the same over the door. I’m having a good feeling about this. Still have lots to do to make it exactly how we want it, but we’re getting closer.