How much pressure is on the cold water line?

I have had between 5 and 6 bar on the pipes for years so that I can use the sprinkler effectively. If the pressure at the faucet is too high, I have turned the angle valve a bit.

When I fill a pool 600l/h

It is only 2.5bar I believe on

If I fill a pool 600l/h It is only 2.5 bar I believe

600l/h means nothing at all. It can be 10 bar on a "small tube" or 1 bar on a 32mm pipe (numbers arbitrary).

3.5 bar is enough for us. I wouldn’t go over 5. If it is so important that only one sprinkler supplies the entire garden area at the same time, run a separate line with a different diameter and pressure for the garden tap.