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

Roller blinds and/or venetian blinds at the bottom are not a good solution for us in rooms where people are currently staying, because we like to have a clear view outside and both bother us. Venetian blinds are certainly a bit better than roller blinds in that regard, but it’s still not really great from the inside when they are down. When you are absent, of course the best solution is simply to close everything up tight so it doesn't heat up.

We have now built a patio roof over most of the south side with an under-running awning. In strong sunlight, simply extend the awning... okay, then you can't look up at the sky anymore, but you have a completely free field of view straight ahead and the sun doesn’t fall into the windows, yet it remains pleasantly bright inside. Since the awning is 4.5m deep when fully extended, we can almost regardless of the sun’s position shade the windows from the outside if necessary.

Google something like this: hydraulic balancing, no buffer storage, no ERR. You will surely find instructions or threads about your heating system somewhere. Unfortunately, I don't know your heating system, but in any case, you will set it better for yourself than the craftsmen.