Hi Leo,
From an API perspective (which it looks like you are trying to use) I do not think there is a Teams API that will return the user's IP address.
As you can see List Participants does not report this back:
List participants
https://learn.microsoft.com/en-us/graph/api/call-list-participants?view=graph-rest-1.0&tabs=http
You can try suggesting this feautre:
https://feedbackportal.microsoft.com/feedback/forum/ad198462-1c1c-ec11-b6e7-0022481f8472