There are already a few requirements for operating the balcony panels, At least here in Germany:

• You need a suitable electricity meter
• You have to register with a relevant authority and inform the electricity provider that you are operating a “balcony power plant”.
• The microconverter should run on its own secured circuit. (“Should”, will certainly do very few) But technically it is simple:

1. Set up panels
2. Connecting necessary plugs
3. Microconverter to the socket
4. Be happy that you produce up to 800 watts of your own electricity

I think it’s almost irrelevant how many panels you ultimately split up. However, no more than 800 watts may be fed in.But if you have panels with, let’s say, 2000 watts, you can of course charge various batteries with them beforehand. Nobody can say anything against it.

Thanks for the new rabbit hole! 😁

Can you briefly explain how this works? Do you have a link or something similar?

This is a basic element of information gathering. Always check the source!

Is the laptop connected to 2.4 or 5 GHz Wirth WiFi? In my setup I never get more than 80 Mbit with 2.4 GHz.