Set the heating correctly

Yes, but you don't need to keep the water at the temperature permanently.

45° is enough, and then have a legionella program run once a month. (Most heating systems already have this anyway.) So heat it above 60° once a month. Keep it at 45° for the rest of the month. That should save some energy.

Otherwise, turn the regulator in the bathroom all the way up and then lower the heating curve until the desired temperature in the bathroom is reached and the room does not overheat without the regulator.

he cannot maintain 55 degrees permanently, I have the eco mode on which means it only heats again from 45 degrees, if I were to turn it down to 45 I would have to set it to continuous heating, I would have to try if that would be cheaper for me

No matter what the manufacturer calls it... the water is kept at a certain temperature... or heated to that temperature...

I don’t have 45 or 55 degree warm water coming into the house... and I don’t think you do either... it is only brought to these temperatures by the heat generator.

But first try out what is cheaper for you...

55 degrees with an air-water heat pump is still quite intense in my opinion

He mentions burner starts and burner run time above. Therefore, I assume that no air-water heat pump is installed. The "Buderus Logaplus package W22 GB172-14, G20" appears to be a gas condensing boiler. Regarding the legionella, the question would be whether there is a storage tank and how large it is.

He writes above about burner starts and burner run time. I therefore assume that no air-water heat pump is installed. The "Buderus Logaplus-Paket W22 GB172-14, G20" seems to be a gas condensing boiler.

OOPS You are absolutely right. No idea how I came up with air-water heat pump.

Then I find 55 degrees for hot water rather less dramatic. For hot water heating, a gas heater only has to cough once anyway.

is written a bit badly,
of course I have a gas condensing boiler with a 170l storage tank, I just realized myself that a 170l storage tank can hardly get Legionella because it is used up quite quickly (at the latest when you take a bath), I have to try it out.

regarding the heating, can I somehow check if a hydraulic balancing has been done?