Chalk paint, how do you handle it?

@all creatives

I have been painting for the first time in 2 days with chalk paint on a black lacquered wooden desk, a brown pine lacquered shelf, and a wooden chair, all more or less roughened. Meanwhile, also a lacquer shelf (Ikea). It doesn’t work at all. Even the second coat doesn’t cover where I apply the brush. Corners that I have to repaint after 10 minutes clump and get thick. Surfaces crumble when I go over them again after 5 minutes. Either it doesn’t cover or the paint runs. If I didn’t hope that this is just how it has to be and that I have to sand everything to make it look nice, I would have already been desperate.
What am I doing wrong?
Using a short-pile roller was catastrophic too: the typical texture like textured wallpaper without covering power.
I wanted a tactually great white desk and what do I have: clumped spots, a waste of time..., for the price of the paint I could have already had a new desk.

No idea
Haven't had the problem so far
Only know easy to work with and good coverage

all more or less roughened

I think this is where the crux of the matter lies. I have found that less and even "more" roughening is often not enough; the old paint should actually come off. And then the usual: clean, dry, free of grease and oil.

I think this is where the problem lies. I have experienced that roughing up less or even "more" often isn't enough; the old paint should really be removed. And then the usual. Clean, dry, free of grease and oil.

Does not apply to chalk paint. I just painted a few boards of the shelf without any pretreatment. Not even degreased. Result: the first side with the white as described, the other side super easy to spread and opaque. The more open-pored the substrate, the more stubborn to spread. That applies to the white. Colorful paints are always better.

So far I have never had any problems and have painted over a lot, maybe it is because of the color? Mine was from Painting the passt

So far I have never had any problems and have painted a lot, maybe it’s because of the paint? Mine was from Painting the passt

PIP, I am currently following along diligently on FB. The paint is quite expensive, but it tempts me, especially just because of the color palette. Overall, it has to be said that I had these problems on all sanded surfaces, mainly with white. The painted shelf (very smooth), which was only slightly roughened, worked better than with open-pored surfaces. I did not pre-treat the intermediate shelves at all: the white paint went on poorly and I used it as a primer for another one, the green went on like butter. In retrospect, a comparison comes to mind: the white is dull like peanut butter, honey, or Nutella, the green like oil, although both have the same consistency. I am now at the sanding stage. The clumsy brush structure disappears, the messy residue remains fittingly with the stamp "homemade".