Hi Asmir,
i also switched from FHEM to HA. For homematic i now use a CCU3.
I dropped all my internecho style plugs, now i use tasmota style plugs.
I sold also all of my crappy MAX! Thermostat and use Homematic now.
Some 443Mhz components might work with rflink or rfxtfx.
FHEM and the CULs are very DIY/homebrew “style”, i think you will never get a support for a CUL.