Hi Rey and welcome to this community!
Since you already have the H 4890 which is a OpenWebNet gateway, you should be able to connect your system to openHAB already.
Once you connect it to openHAB with some patience, learning and configuration you would be able to connect to assistants like Alexa, Google, etc. and to have a mobile interface for smartphone and tablets.
Regarding discovering your IDs and configuration: the openHAB binding should be able to discover all your devices automatically, which you then can add and further configure to connect with assistants.
You will find real experts on BTicino systems here, I suggest you consult this other threads:
- BTicino/Legrand Home automation general discussions: openwebnet protocol
- and maybe you can find useful this very well writte guide by @the-ninth which has followed a similar path (migration form pysical to virtual configuration, migration of scenarios to openHAB, connection to Google/Alexa) etc.: BTicino/Legrand Home automation general discussions: openwebnet protocol - #48 by the-ninth