I am using the official Shelly integration and the Fritz!Box device tracker integration.
Home Assistant notices, that the entities of both integrations belong to one and the same device.
As such, I get the device tracker attached to the Shelly device, which carries the IP address in an attribute.
Having the IP address would be nice to send rest commands to create sensors, i.e., to open a roller using “duration”, which unfortunately it’s not implemented in the integration, only “position” is.