Will drywall mud adhere to semi-gloss paint?
I have roughed up the surface with red scotch brite pad or by sanding (scotch brite doesn’t make as big a mess).
Then wipe with a damp rag to remove the loose particles after that the mud will stick I have done this hundreds if not thousands of times on my own home and remodels, rewires where I had to patch holes used to drill and pull wire. + Jimmie fix it method may be a better way but takes time and I have not had failures.