He had to be saved by Dany remember? Mereen was under siege when she she returned and all he could do was
I actually have liked Tyrion this season. He's been great politically imo, esp as it pertains to uniting Jon and Dany, he's just been outwitted by Jaimie militarily. And that's to be expected going by their history. Jaimie was trained at tactics. Tyrion played a neat trick at Blackwater and he played a neat trick to capture Casterly Rock but war strategy is not a strength of his and it never has been, even in the early seasons. Tyrion has always excelled at cultivating interpersonal relationships and working his wit and he's done that fine this season.