Stand aside! Paint expert coming through.
what? Qualifications? This is the Internet, lads. Come on.
(A summer as a student painting bathrooms with Zinsser on Staten Island to pay for a driveaway car trip across the States; six years as a sign writer and bespoke painted furniture / kitchen cabinets / mural painter; BSc in Paint Science from Dulux College, Cambridge. One of these is a lie.)
Take off the Valspar. Rough back the emulsion ( it’s a bit like the joke in Ireland about directions “I wouldn’t start from here…” You’re not going to go back to plaster and put on Zinnser BIN so you will have to trust the emulsion is on right and not trapping any oil or solvent…) to make a key and use Bullseye 123 as a base. Two coats, with at least 90 mins drying time between coats and an overnight before the topcoat. Your second undercoat can be tinted towards your final colour if it’s desired. Anything waterbased as topcoat, but don’t go cheap. Specialist bathroom paints as top aren’t really any more wipeable than good emulsions imho.
Things will be better now, but we would be off our nuts on Zinnser by lunchtime. VOCs. Keep the windows open!
If you’re bothered about the environment and your health - having looked at VOC off gassing I now steer clear - I recommend Mythic Paint, but I don’t think it’s freely on sale in the UK. Also Lakeland Paint. Zero VOCs.