If that wikipedia article is right, then balcony solar is not legal where I live (in the US). Here, we require a hard-wired, permanently installed automatic transfer switch that disconnects the solar generation from the grid when the mains power goes out. This is to protect line workers when working on downed lines.
It's probably coming soon for you, 30 states have bills announced or introduced legalizing plug-in solar and one (Utah) has already passed. They should be fairly uncontroversial.
Also, there's no need for a transfer switch in any grid-tied system, whether plug-in or hard-wired. Grid-tied inverters shut off automatically if there's no grid frequency to sync to.
99.9% of all inverters currently being sold has this functionality built in. That 0.1% remaining you will find in the second hand market and the bargain bin of Amazon.
We require transfer switches, but they do not have to be automatic transfer switches.
In the United States, you are one small piece of sheet metal[1] away from any number of interesting power set ups on your side of the utility.
This means a combination of two circuit breakers is now your transfer switch. This is legal with all utilities and NEC compliant, etc.
If you are willing to sacrifice perfectly uninterrupted power, you can dramatically simplify your grid tie - and open up many other possibilities on your side of the physical interlock.
[1] https://www.daierswitches.com/products/sd-200vl-generator-in...