switchable high-power socket

Sorry but I don’t understand that. The two photovoltaic systems are available to the household. That means if you plug your car into a socket, the photovoltaic power will be used for charging instead of power from the grid, provided the photovoltaic system is generating power. I also don’t understand what you want with two sockets, especially since I understand it like this: one socket would be for photovoltaic system 1 and the other for photovoltaic system 2. But that’s nonsense if both systems are connected to the house grid. Or do you mean to leave the car plugged in all the time and only start the charging process when the photovoltaic (whichever one) is generating power?

I actually didn’t want to tell the whole story but okay... There are 2 photovoltaic systems – one of them feeds a heat pump. It also has its own heat pump tariff. And then there is a second tariff for "lighting power." So we have two tariffs in the house. And if we charge the car in the morning with "east power," as the sun moves throughout the day it decreases and thus the "free" power also decreases until around 12 o’clock the sun shines fully on the west side. And then we just want to "switch over" to get the full free solar power for charging. The difference between what the car draws and what the solar system produces, we have to get from the grid. And we want to keep that as small as possible.

Please order a friendly electrician to come to your house. From your explanations it is not really clear what the current situation is and what exactly should be changed.

The electrician is coming anyway. But I would like to inform myself in advance about what is possible.

Integrating the car into the circuit with the photovoltaic system for the heat pump leads to the car being charged with the heat pump's electricity. This is probably at least against the [AGBs].

Your setup is generally unfavorable. Remove the heat pump tariff to make the output of both photovoltaic systems available to the heat pump and all other consumers.
Alternatively, you can talk to your electrician about the [Messkonzept 8].

For my old system on the west side, I even receive 16 cents compensation for every kilowatt that I consume myself. For the new one, I no longer get that. For that reason alone, I cannot "combine" them. That's why I would really like to implement my idea.

Measurement concept 8? Can you explain that to me in more detail?

Each system retains its own inverter. Nothing is combined in this sense. Talk to your electrician. Please enter the measurement concept on Google. It allows the use of photovoltaic electricity also for the heat pump, even though it has a separate meter/tariff. Personally, I would keep it simpler and just remove the heat pump meter.

Okay, all clear. Thanks anyway for the help. I would have liked to know if there is such a "Starkstromzeitschaltuhrschalter," but oh well.

Yes, it is called a Schütz with a timer or another logic in front. As already described at the beginning.