Another plot could involve the OC being from a different dimension. Dillon discovers that the OC's dimension is somehow linked to the threat they are currently facing as Power Rangers. They have to work together to close the rift between the dimensions while also dealing with their growing feelings for each other. Maybe there are some cultural differences between them that add both humor and tension to the story.
A possible plot is that the OC is an outcast in their own community and Dillon relates to that. They form a bond over their shared feelings of isolation. The story could follow their journey as they try to prove themselves not only to the other Power Rangers but also to the world. They might face a powerful enemy who targets their insecurities, but together they overcome it and their relationship deepens.