The paradoxes will be relevant at the climax of the story, they're mysterious~
But you need to make sure to have both the yellow and blue mementos as well or the paradoxes won't work.
We've got a walkthrough here in case you're having trouble getting the endings ✨ https://fablenovel.itch.io/hummingbirds-crown/devlog/399601/walkthrough-some-spo...