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

I now believe that the Novelan WP

This valve is felt in almost all WPs

Suddenly he starts messing around with the settings and just wanted to raise the hot water temperature, heating curve, and heating limit.

These are settings that satisfy 95% of customers. The house gets warm, the bathtub gets warm. And whether the heating cycles or not, you usually don't even notice.

The problem mentioned here should therefore occur just as well with a gas heating system, and the reason is to be found in the underfloor heating rather than in a heat pump or gas heating system.
Or am I wrong?

A properly designed underfloor heating system in combination with a reasonably insulated house has such low supply temperatures that when external energy is added, the floor can physically no longer release energy. --> Self-regulating effect.

Neither a fireplace nor a radiator can do that.

Therefore, the room temperature is actually easier to regulate with underfloor heating than with anything else. Theoretically, it even allows you to feed the energy from a fireplace or the sun back into the system and thus into the other rooms. But whether this will ultimately show up on the bill... no idea.

I have now also played around with the heating curve so that it is 22.5° degrees for me. All thermostats/valves open. However, I do not know if the settings are correct. My heat pump is also cycling like crazy.

Then something is wrong. Did you just turn everything on and that’s it? A heat pump cycles when it can’t get rid of the heat, so I assume your heating curve is not right or something is blocking the flow somewhere.

The problem mentioned here should therefore also occur with a gas heating system, and the reason is rather to be found in the underfloor heating system instead of in a heat pump or gas heating system.
Or am I wrong?

You are wrong, a correctly adjusted underfloor heating system can (almost) not overheat the room.
If the rooms become too warm, it is due to incorrect settings or solar gain.
If the underfloor heating only provides 22 degrees, it cannot heat to 26 degrees.

Ok, both answers make sense to me; I also assume a very casual attitude and interpretation here, over which I unfortunately have no influence. It is supposed to be different in the new building. Here, a towel radiator was connected to the system for each bathroom, and we could turn the wheel for hours, nothing happens. Meanwhile, I also know why, from what I read here. This was probably more of a quick action by the former owner, which is actually a shame for such a beautiful property.