Annual performance factor calculation for funding (parameters and calculation tool)

What are possible and justifiable supply and return temperatures in a very well insulated house (KFW 40+)

Heating limit temperature 12
Flow 30, return 23
the rest default
makes 4.57 without cheating with hot water
So no problem. Is it a modulating heat pump?

: Unfortunately, I cannot answer everything. It is controllable, if that is what you mean. "Modern air/water heat pump for heating, cooling, and producing hot water. Split design, modulating."

Modulating is the magic word. It would also be interesting to know how wide the control range is.

under what do I have to search there or what is indicated there, then I can search for it

technical data sheet
the performance at various operating points is then specified there
for example A2/35 means heat output at an air temperature of 2°C and a heating water temperature of 35°C.