Hope this helps you:
I have used a Rustoleum kit meant for refinishing before but wasn't impressed. This looks better https://amzn.to/3a2mzgU
Here is how I painted my kitchen cabinets - no sanding needed! https://happydealhappyday.com/how-to-paint-kitchen-cabinets-without-sanding/
Paint the cabinets then stencil designs on them for a vibrant view when persons enter.
Take a good photo or one of the cabinet doors to the paint department at your home improvement store and ask for their advice. They have products and ideas you may have never thought of.
Use a good stain blocking primer, lightly sand, and then use a satin or semi-gloss paint. I really like satin and it is washable. No need for a sealant when using satin or semi-gloss. I also like to use a sprayer on cabinets to avoid brush marks.
You could try painting them with General Finishes milk paint. It comes with a matching primer and sealer. I used it to paint my kitchen cabinets, and they turned out great! https://momhomeguide.com/my-painted-kitchen-cabinets-a-year-later/
Here is a very good article https://www.architecturaldigest.com/gallery/bookshelf-paint-ideas
Select paint color wisely. While you are at it, paint the walls too.
Try painting the inside of the backs of them a dramatic color for contrast!