High-pressure cleaner, but which one?

I have a Kränze Quadro 599 TS T with some accessories. Due to the four large wheels, it is very mobile. But it is overkill.

Check with the manufacturer of the plaster and the terrace slabs. Many advise against using a pressure washer

Yes, that is true. It feels like almost every manufacturer says, do everything with my material, but please no pressure washer :-) The manufacturer of the pressure washer sees it exactly the other way around ;-)

Concrete is particularly not recommended, although it’s all a matter of pressure in my opinion. We have a tiled terrace (ceramic), so the thing works well for that. I also gently spray the blinds with it before the window cleaner comes. It’s also been used on the car once, with the appropriate nozzle.

Yes, that's how it is, and if you hire a professional, they will also come with their pressure washer to clean your concrete pavers.

Kärcher has 2 types: Consumer and Commercial. There is a price and quality difference. The commercial line is not available in hardware stores, but at specialized dealers or agricultural machinery dealers. However: in my opinion, it is not necessary. My own HD is from WORX and runs and runs and cost 99.00 euros at Hornbach in Lübeck.

Yes, that's how it is, and if you hire a professional, he will also come with his pressure washer to clean your concrete paving stones.

No. Real professionals who make "old" into "new" do not use a classic pressure washer.

Kärcher is, in my opinion, overpriced cheap plastic junk. After my yellow Lidl HD cleaner, which also gave out halfway just because of frost damage, I supposedly got the "best" Kärcher. No difference from the Lidl thing, or rather the Kärcher, at its high price, doesn't even have a way to roll up the hose. I found that really ridiculous and I get annoyed every time I have to take it out and put it away again.

If you really don't have that much to "Kärchern," then a no-name product is more than enough. You really have to consider how often you actually use the thing?