I’m not sure Somfy actually sell the blinds. As far as I know they sell the motors to blind manufacturers. They seem to have a huge range of motors and it’s often difficult to know which one a manufacturer has used.
Maybe the situation is different in other countries.
If you want control with Alexa then you will need a gateway of some sort as they are not directly connected.
Tahoma and Connexoon are Somfy’s official bridges.