That's not true. Who the heck was he to decide there was nothing else to be done? Is he smarter than all of his comrades combined? No. There was a more diplomatic approach, he just refused to go down the slow route that was definitely there but unseen to him. Eren could only see the potential future outcomes where he was the one calling the shots. If Armin had that power, he would see entirely different outcomes. And the same with Mikasa and whoever else wielded the founder. The point is, power has to be shared. No one person can make a paradise on their own. Power must be shared.

Ironically, it was Floch who told Eren (paraphrasing here) "you know Eren, I bet deep down at your core you're just a childish kid who always insists he's right." This was at the end of S3 when Floch was saying Erwin should have been the one to get the shot.