Hi,
how and with what did you integrate the inverter into Home Assistant? If you have/use a Growatt Shine Stick you can flash ESPHome on it and then integrate the inverter with Home Assistant via ESPHome. See:
FYI: GPIO0 and Ground must be connected by a bridge so that the stick goes into flash mode.
With ESPHome you can set the Max Output Power for the inverter
number:
- platform: modbus_controller
name: "${devicename} Max Output Power"
address: 3
value_type: U_WORD
min_value: 0
max_value: 100
entity_category: config
and use it for/on automation. If … then set Max Output Power to 50, 25, 10 or whatever.