The true ending is intentionally allowing the war to take place just so you can have a pillow fight with Myka.
Jokes aside, I loved this story. It's so interesting going back and replaying the first loop and realizing how tired Jo is and how much work they did behind the scenes with saving Suzette and warning the generals. It's also kinda ominous if you take the History path on the first loop and Jo isn't there. You really feel their absence. It makes you think that at some point Jo had to have blown up the damn to find the ancient word (unless they found some other way). I really wish I could go back to that original Jo and tell them about the the corrupted land. Or at the very least be able to heal the corrupted land with new Jo. Getting Jo to remember would've been the most cathartic ending in my opinion. But at the same time Jo did choose to stay in the life that they did so it would be unfair to pull them out of that.
Although I think it could work if you found a way to back to the original loop. Like if there was an ending where you brought Mr Pent to the tower and he let you reset the stone to its original state with both your memories and Jo's memories in tact. I would just love to see Jo makes snide remarks about how "Shocking" my choice is until it sinks in that I actually remember and then we both solve all the problems together.
I think the highlight of the entire story for me was blowing up the dam with Myka and seeing her reaction to the witch monster.