dragons are not rigged , its the whole mode that is ,the winners are pre-determined even before you choose your 1st card .
What ever tribe you choose you’ll stop seeing them around rank 3 , unless your ele’s in which case you wont see them from rank 2.
If your playing a tribe specific hero if its your turn to win you’ll get everything you need in abundance , but if not the game will appear like its screwing you over every turn , we have all experienced this