How to prep these walls before painting?

[sentur]

I’ve stripped previous owners wallpaper off a couple of walls in a 1st floor bedroom. Typical terrace property.

The wall surface under the wallpaper looks like a mix of paint with patches of raw plaster.

What do I need to do to prep these walls before painting with the coloured paint (top coat)?

In other rooms where there’s no wallpaper I’d fill any dents and holes and sand those areas back. And then paint a couple of topcoats over the top. Never normally prime them with white unless the colour is very dark or a specific reason.

Attached a couple of photos of the wall surface

 

[Wayners]

Bodge cheap orbital sander on a vacuum with 120 grade.
That will take paste off then fill over wall with toupret powder filler.
Some use a ready mixed wall smoother but I think the toupret can be easier and cheaper if not too bad.
Orbital sander again with 180 grade.
Gardz to neutralise any remaining paste and seal the wall ready for emulsion.

Option 2.

Spot fill
Sand
Gardz
Paint