High-pressure cleaner, but which one?

Yeast? I don't know yet Fresh or dry I know baking soda or washing soda

Works great! Otherwise, a cheap device from Lidl & Co. is actually sufficient.

Yes, that's the trick: if they run less hot, even cheap devices last longer ;-)

Our pavers also strongly advised against using a high-pressure cleaner. They said it damages the surface of the concrete stones and they would get dirty even faster as a result.

But aside from baking soda/soap/yeast and scrubbing manually with a brush, are there any other alternatives? Probably not?
Is the mechanical stress of scrubbing really gentler on the stones than the pressure washer? I really can't quite imagine that.

If it is only about green deposits, Mellerud helps, applied with a pressure sprayer

With a motorized brush, it also works for larger areas or dry ice blasting…

Scrubbing is good for the muscles, metabolism, and with a fast pace it replaces cardio training.