Welcome to FT!

The direct option EWR-DBV would of course be most convenient, but I take it that there was no award availability when you originally booked? Also, you say this would require you to transit from A to C at EWR; are you starting your journey somewhere else, and is that on a separate ticket? That could throw up some issues as well.

To your original point, UA Gold / *G isn't going to make much difference in this case. It is tight, but doable in just over an hour. I don't know what later flights there are out of YYZ to FRA/MUC that evening on AC or LH, but AC would rebook you on one of those if you did miss the original flight and all of this is on one ticket. There is, of course, the distinct possibility that another flight on this itinerary is retimed, so keep an eye on it, but no reason to worry now.