A couple of things, its not unrealistic to have difficulties with your first run of a week 1 fight with it being your first time seeing the fight in action, you cant see the future, and there's no harm in losing the 50/50 guess on an attack. And even then, its fine to not be perfect at the normal content. Even playing Extremes and savage content, I still struggled with the new normal raids, and didn't go without dying on a single one of the 4 fights.

However, I don't think its derogatory to say that OP has a skill issue if their argument is in bad faith, as it comes from a place of entitlement after not being catered towards, and is in my opinion, unhealthy for the game. Especially considering the healer strike on the forums due to mind-numbingly easy healer content in dungeons prior to Dawntrails release.

Lastly the devs never changed the difficulty in any of the normal content in Endwalker, never changed crystal tower series, never changed the majority of content in the game to be harder, they are as easy as they always were, and you can still play that if you want easy content, and they are creating more casual content in future content cycles like cosmic exploration. They did however make Endwalker so easy, so unengaging, so bland, that Thaleia wasn't even hardly an alliance raid in difficulty week 1. Hell, it was hardly a normal dungeon in difficulty. There comes a point in a game where if it does not become more engaging, and expect more of its players, it will become stale. OP wants combat to remain stagnant, because any failure or deviation from the formula is bad.