Underfloor heating air-water heat pump. House too warm when the sun shines

Brief update on the behavior of my heat pump: after readjusting the settings with the help of Daniel-SP, I have been able to halve the compressor starts from 40 to 20 in 48 hours, 10 per day.
That is already very satisfactory, especially since it is much colder now than a few days ago. Last night -7°
The pump now runs for much longer stretches. Great!
My heating curve is set at 29-22-0 and makes the rooms comfortably warm; we even managed to get 21° in the bathroom. We have to be satisfied with that.

Right?

Comfortably warm and 21 degrees do not match. But these are personal feelings.

I believe there are also different theories. I'm going to test now (although modulating) with 1 degree less setpoint at night and 1 degree more during the day.
You probably won’t notice the nighttime setback in the room temperatures much, that consideration is correct. However, your screed still cools down. So the next morning you have the "problem" that when you turn it back on, more energy is needed to reheat the screed. The question is what is more effective, and I have read several times that reheating under certain circumstances uses more energy than you save by switching off at night.
Maybe try it "gradually." So only throttled? Does your pump have a night mode or something similar? Testing only makes sense if you aren’t adjusting other settings at the same time.