I’ve been playing Brilliant Diamond & Legends as if they’re the same game and my character has traveling back & forth between time periods (like Kagome from Inuyasha) using her arc phone. Basically she gets called to Hisui whenever one or two of the nobles goes into a frenzy & then she goes back to the present once she quells them &/or she does something to keep the timeline in order (ex- giving a Torterra to Colza & the farm since it’d become the ancestor to Gardenia’s Turtwig) until she goes back for another mission.
Ultimately, I’m planning on going back once I beat both games, but I’m debating on whether her Pokémon would want to go back with her, especially the ones that were caught in Hisui