Shutter Controller use case is done. I am super happy with how well modular system behave for that. It does exactly what I want and I've already see great potential how to extend it to next usecases.

But first it was needed to put the boards in the cases that have DIN mounts. It was not super easy as some adjustment had to be done on each but final effect is satisfactory:

I had to also configure ESPHome to make all my requirements. I would not get into the details here but instead I've created repo with all the configuration:

https://github.com/smigielski/EasyLink/tree/main

Feel free to discuss it there or here. 

The last step was installation into the DIN rack and replacing all controller with the smart one.

What I can say, it works super great and it was fun to do that. Now I can control my shutters from buttons close to the windows as well as Hass.io. Also, I can adjust everything to my needs and customs of my family.