Hi Johan,
Today a very interesting update was published to the SolisCloud integration for Home Assistant:
I now can turn the inverter on/off with a flow 
, and, it uses the API (not modbus).
The used code is available.
The power limiter seems to work sometimes
When testing, the main problem is the 5 minute wait for the cloud sync. I often forget what I was testing hahaha.
Limiting seems not yet 100% compatible with my inverter
