Get rid of the vault is the #1 solution. Kitchens don’t need tall and odd shaped ceilings. It makes things harder and more expensive. It’s a work room.

Getting rid of the vault is not really an option at this point nor would I want to. Ceilings are only 7'8" on long side of kitchen and max height is 9'6" before it slopes down again into the living room.

Recessed cans for sloped ceilings is your ambient lighting; undercabinet is your task lighting. Do you have an island or other work space that can’t be illuminated by undercabinet lighting but will require task lighting?

Edited to add that I just reread your OP and saw that you do have an island.

I have an 8ft window so can't do the under cabinet lights on that wall. Was planning on 3 pendants over the island.