Do they know it was Cersei? Do they care? Sounds like Tarly support and whatever else is left in the Reach is enough to keep King's Landing fed.
The love of Euron was overkill, as is Euron's speed of travel but I've started ignoring that since Varys' little teleport to Dorne and back. Although to be fair no one said an episode is 1-2 days, some chronological differences are allowable. That doesn't explain all the plot holes but I give the show a bit of leeway since it's still fucking good entertainment.
And that episode was vintage GoT really. The tactics behind all the moves, from Tyrion devising a plan into Casterly Rock to then Jaime/Cersei handing his ass to him and his plan takes me back to peak Stark v Lannister strategy. That said, it does feel like the classic villain-on-top-before-downfall arc. Yeah, GoT goes against many customs but you think how High Sparrow seemed untouchable midway through S6 and here we are. Tis a cruel series but no way Cersei comes out on top in the end.