Hi’
Just some comments, as I’ve just finished my ESPHome Solivia Gateway M1 G2 modbus sniffer 
If you want extended details from your inverter, then an ESPHome modbus sniffer is the easiest and simplest solution.
Many commands are now public available and a few guys have identified and posted the majority of registers in the different inverter package replies. There seems to be at least three different package lengths out there. All depending on model and firmware.
My specific inverter package differs a lot in both length and the registers index in the package from other examples I’ve found on the net. So I had to do the job from scratch. Only missing a few unknown registers now 
If you’re interested then take peek at this thread. I’ll publish my final config in a few days.
Regards
Henning