Came across this question via a Google search, but one possible solution is outlined in this earlier post.
I’m using Node-RED to create two sensors - one for latitude and one for longitude based on the geocoded_location sensor provided by the mobile app integration. Similar to the linked post, the state of those gets inserted into the templated iframe URL.
At least, that’s the theory! I’m having some issues getting the iframe to actually render using this approach. I’ll update this post with code if I can get this working.