Posting the solution here so other people can find it:
Retrieving the execution data allows to get the token usage by the model.
This was posted by @Antony_Eardrop on this topic here
Since the solution provided by @jcuypers contains this information (although it’s a paid one) I’ll mark his reply as the solution and append my reply on my question at the top.
This way both useful informations are easy to find by future people having the same issue.