In topic Universal Solar Inverter over Modbus RS485 / TCP custom_component (Growatt, Sofar, SolaX, Solis) I found a tcp/modbus solution,
If my solar system is more or less equivalent (manual look very similar) then I could expect the rs232 port spitting out modbus like packages. (haven’t tried that yet)
In topic Smart meter integration via RS485-USB I learned that Homassitant itself (ie without esphome) should be able to read modbus packages.
If my device spits modbus data over rs232 (that normally connects to the wifi dongle) and I have some kind of modbus decoder like in the first thread, I thinkt it should be possible to read my solar without middleman like node-red or esphome.
As these topics are fairly old I assume somebody else might have tried and succeeded the direct (Solar-HA) solution. Have not found it yet. Any hints?