Experienced cabinet painters- advice needed!

I moved into a house where the previous owners painted their builder grade cabinets—upper cabinets are painted white and the lowers are painted a gray with purple undertones. I’m not yet sure if if I want to paint the lower cabinets white or a different color of gray. My question is...how do you paint already painted cabinets?Should I strip the existing paint off first or can I paint over it?What prep work do I need to do if not stripping old paint?What kind of paint...oil based, chalk paint, milk paint, or I’ve read BM has a great one for cabinet, or other?

Ideas on how to decorate walls that have a high & angled ceiling?

The fireplace wall is 14’3” and the fireplace is H=4’9” W=6’ D=25.5”TV wall is 11’9” and the window wall is 18’. This room is open to the kitchen. Any decorating advice is greatly appreciated!
q need advice on how to decorate walls that have a high angled ceiling