And if someone else becomes Champion of Alola, we could have something similar to what happened in the Pokemon Anime where Ash, as Champion of Alola, battled Leon, Champion of Galar.  One thing that could be good too, is if they lose to Leon and his Gigantimax Charizard, which would spur the journey through Galar to get stronger and master Dynamaxing and Gigantimaxing.  Also, if you'd like, I can PM you with my ideas reguarding Tru and Chuck.