PVA on it's own, when used as an adhesive/bonding agent, is only effective in its wet/tacky state..
If you let PVA on a wall/ceiling etc dry out , it becomes just a dry smooth surface, (similar to a coat of paint), a barrier with no bond for the plaster, and if you plaster etc onto it, it will not adhere, and eventually fall off...... If the PVA does dry too soon, just go over it again with another coat when your ready to plaster.
If you PVA a surface and plaster straight onto it while it is still wet/tacky, "it will bond"......
You can add cement, plaster or even sand to PVA to make a slurry to brush onto a smooth surface to form "a key", which you "would" let dry out first, before plastering etc........
With artex that is sound, knock off the high spots, coat with PVA, and again,while still wet/tacky, plaster straight onto it...........
As an aside,,, there are many people on here with a great deal of knowledge and experience covering all of the trades. Most of us do it for a living every day, and are only too pleased to share our experience and knowledge with those who want some advice, that can maybe help them solve a problem..
Roughcaster.