I found that this solution worked:
Collection.rawCollection().aggregate().toArray()
Interestingly, I’m still getting a
reactiveTable error: argument is not an instance of Mongo.Collection, a cursor, or an array
error in the browser console although the session vars do get set just fine.
There is a note in that linked post above from robfallows about using async/await as well and on my first try was not able to eliminate the client side error but it could be my ugly factoring. I will post an update if I’m able to resolve.
One note, for some reason I don’t have to do this for ALL of my aggregates. Just a few.