The 21° in the bedroom and dressing room are also unfortunately a compromise; the large bathroom is directly adjacent to the dressing room, separated by a sliding door. I have found through multiple attempts that when I turn down the temperature in the bedroom and dressing room enough to make it really cooler, the dressing room then draws energy from the bathroom floor. So if I want the bathroom to average between 21.5° and (sometimes) 23°, I must not turn down the adjacent rooms too much.
At some point, however, I also reached the point where I no longer care about every single kWh without punishing myself and my family. Thanks to photovoltaics and storage, the past heating season was practically free; for 2019, we had an all-in electricity purchase of 5000 kWh and fed in 6300 kWh. And that with 5 people across 2 complete households. Of course, it would be nice to need even less..... but maybe I should keep things realistic.