No. With heat pumps electricity is way cheaper for heating.

Only on nights with temperatures below -5 Celsius gas is cheaper.

The problem is that most vendors are sold out.

I think is true for single detached housing, is it also true for larger apartment complexes? I bring this up because in Germany I believe most of the population does not live in detached housing or semi-detached housing.

With larger apartment complexes it may be economically feasible to pursue geothermal heat. In this case a more efficient solution could be a heating arrangement using hydronic heating combining geothermal heat, waste heat, topped off with an efficient large-scale boiler (the apartments need hot water anyway), and then pumped into radiators or underfloor heating.

And naturally the most efficient solution of all could be district heating.

Our apartment complex uses a gas micro power plant to produce electricity and uses the waste heat for heating/warm water. It’s a building of its own on a compound with 20 or so apartment buildings. Replacing that with a heat pump will require some very serious planning efforts - apart from the requirement that like 1000 individual parties in 20 home owner associations would approve the change. Not going to happen this year.