@Claudiusx
I had used only mealworms and superworms for some months as I had no access to dubias. (Was fine with doing so, dragon is healthy, not overweight).
I use them more sparingly now (adult dragon, easily eats veggies, does not tend to overeat (can leave him alone with a multiple-day supply of insects and when I come back there are still some), often even refuses superworms when offered both them and dubias - preferred superworms when younger) but not as rare as a "treat" would be.
(For me, I would define a "treat" as something super rarely fed and even considered as "too high in calories, but I can live it with my pet eating it to get the medicine down", "once in a while as a surprise" and thus should not be a major contributor to the average calorie intake. Like: cat and a can of tuna. Or: human and ice cream.)
Regarding "facts" (as they are very important to me): Are there any reliable studies regarding what wild bearded dragons eat? (I know this can also be misleading as likely on average they would have to be more active.) Nutrition value of different feeders vs. what bearded dragons need?
Observations like yours give us valuable hints as "anecdotes" (what they are, scientifically: a small number of cases), but if there's more, e.g. research, that would be interesting.
Regarding nutritional value I found for the superworm: 46.80% proteins, 43.64% lipids, 8.17% ashes, 1.39% carbohydrates (source:
https://www.sciencedirect.com/science/article/pii/S0889157518312195?via=ihub, maybe not accessible to everybody, I accessed it out of a university's network)