so played around a bit with it and found a way to do this relatively easily, tested and looks good. The details to construct the link are actually in the entity state + attributes
this is the template i used to generate the link, where
image.guestnet_qr_code = qr entity from the unifi integration
entity_picture = link to the api with token embedded
state=timestamp that is used in the actual url
http://hassio.local:8123{{ state_attr('image.guestnet_qr_code', 'entity_picture') }}&state={{ states('image.guestnet_qr_code') }}
note - the token changes frequently, but using the template ensures im always pulling the current one being used by the integration
bit of a hack but it works ![]()