btw you have a misunderstanding here across the threads about the European grid topology.
en.wikipedia.org
If you have an inverter with a bond between its GND and "neutral" output, then it is actually a PEN output, NOT N! It should not be labeled as GND,N,L - instead it should be labeled as GND,PEN,L. You cant hook PEN into one of the inputs of an autotransformer to make 240/120 split phase, where the center N of the split phase output is grounded! Common misunderstanding.
Reference:
https://www.normadoc.com/english/din-vde-0100-540-vde-0100-540-2012-06.html
If your EU model inverter has a GND bond then it is designed as replacement of the utility power, so it has to be hooked into the house connection point, same way as the utility grid is (and not just somewhere in the house, like an input of an autotransformer).
Another misunderstanding: autotransformer is not same thing as isolation transformer with two 120V windings in series. On the autotransformer you can potentially get the whole 240V power input out of one of the 120V legs, while isolation transformer will be designed in a way to allow to draw only half of the 240V power from each of the 120V legs.
Same holds for the popular split phase inverters like 6kw MPP, you will not get 6kW from one of the 120 legs! You can rather imagine these units as two 3kW / 120V inverters working in series. Each subunit will give only 3kW on each 120 leg. So autotransformer solution is clearly superior and cheaper than split phase inverters, but certainly poses some security risks.