I had exactly 0s downtime for heat pump electricity in the last 15 months, and current houses are insulated well enough that a few hours are really not a problem.
In my opinion, the heating is not the problem at all. Rather, it is the hot water during non-heating periods. However, this may also depend on which storage tank and heating system are used and what the showering and bathing habits are.
To my layman's understanding, blocking times will only become a problem in the future. Very cold winter and very little energy on the market. That will be the absolute exception, but probably then when the heat pump should be running best because it is designed for the standard outside temperature that applies at that time.
As soon as affordable electricity storage for household use becomes established or achieves a technological breakthrough, the issue should soon be resolved.
With heat pumps, there are blackout periods. We were not informed at the beginning and once wondered why there was no hot water. The storage tank simply ran empty.
The blackout periods are from 12:00 to 14:00. The plumber also said that, in his opinion, it is nonsense; they should have done it at night. Only then is the energy demand lower anyway. And yes, at the beginning our pump stopped frequently (software error). It takes days, not hours, for a KfW house to get cold.
12-14 o'clock I find a strange time. Actually, it is supposed to catch the consumption peaks, and that should be in the evening and early morning, when everyone has the lights on, is heating, etc., and not during the day, especially at times when all the photovoltaic systems feed in most of the electricity.