I personally really enjoyed Engage's story all the way through. The story knew what it was and what it wanted to be; little did it feel like it wanted to be a 100% legit war story, if just a telling of Alear's journey as an emblem. Though, I do feel like the story peaked at 22 and anything after that were the writers throwing ideas at a dart board with very little elaboration because there were only so many chapters left. Even for me, the entire time travel thing was just kind of unneeded and if they wanted to still pull the same idea of Alear fighting their past self, some sort of "we gotta fight fragments of the past now for w/e reason" deal would've worked just as fine.
Ultimately, I still feel like the game wrapped nicely despite the shaky last stretch and overall, I had a really fun time.
I think it's easier to take in Engage's story if you rationalize it as a shounen/kids anime sort of story and personally, I think that fits. Engage is supposed to be an optimistic celebration of the series and it sure does nail the tone of one.