Have you tried carnation instant breakfast? It has 13g of protein in one serving and has a variety of flavors. You can buy them premade or as a powder and add milk. I personally prefer adding my own milk.
Or if you can’t do dairy, ensure clear has 7g of protein per severing and both flavors are tolerable as long as they are severed chilled. Ensure clear are more like juice, but have a mineral-y taste when warm.
You can buy them both on amazon and I know grocery stores carry carnation instant breakfast.