Uneven texture on walls

Hello

My corridor has a very textured finish to the paint. It's much worse then orange peel, it looks like someone has painted it with a masonry roller. I've run my Aldi drywall sander over it with 80 grit which has taken off the tops but still the texture is there.

Where I've filled patches the wall is now smooth. The contrast is clear. What is the best option to flatten everything? To me this is what a drywall sander should excel at?

This isn't artex just really thick lumpy paint. See the attached picture.

There is about 10m2 so if it came to it I could try trowelling on a thin layer of toupret and then resanding the wall gently. Hand sanding with 80 grit is gouging and I don't understand why the drywall sander isn't sorting it.

I had to sand back a badly painted extension. Unfortunately I'd already mist coated the whole place. Unpainted, the drywall sander would have flattened the walls back to perfection in no time.

Painted, the drywall sander stripped paint for about 10 or 15 seconds before losing abrasivity (I'm aware it's not an actual word) and just polishing the paint to a diamond hard glass like coating. I went through £50 of sanding discs. Absolute nightmare. Using a random orbit sander saw discs lasting a lot longer but the smaller surface area of the sanding pad meant it took longer to sand the area.

In my case, I think the heat generated on the surface by the drywall sander spinning in a uniform circular motion caused the paint to glaze and harden, thus blunting the sanding disc.

Is it possible yours is doing the same frustrating thing?

Possibly but I'm not sure what I can do about that.

Would a pole sander take off that much texture? I could always use on, then run the drywall sander over the top if necessary to remove any gouges.

In the end I wet the wall and covered it in fine surface filler using a flexible filling knife. Quick to do and barely needed any sanding. It's worked well. Only took an hour or so.

Powder filler (toupret) didn't like going on that thin but Screwfix No Nonsense premixed fine surface filler was fine.