How to use MS Graph to get full details of online meetings of a user

Question

I'm trying to get the full details of online meetings of a user. Using Graph API calendar view, we can get the list of online meetings for a user, including the join URL. For our application, it is needed to get further details, so we lookup additional details about the meeting using:

GET /users/{userId}/onlineMeetings?$filter=JoinWebUrl%20eq%20'{joinWebUrl}'

https://docs.microsoft.com/en-us/graph/api/onlinemeeting-get?view=graph-rest-1.0&tabs=http

This works if the meeting was created by the user identified by userId. Being a participant is not enough. Otherwise an error is returned (The requested resource is not a collection. Query options $filter, $orderby, $count, $skip, and $top can be applied only on collections.) The problem is that the user who created the meeting might even be an external party or have an unknown user object id. So we cannot get details of all online meetings for a user.

The application has the permissions Calendars.Read and OnlineMeetings.Read.All.