Ah thank you! I can add FE3H and FEW3H to disambiguate the tags.

Three Hopes came out this past June as a spin-off of Three Houses, which is the main series title. None of the other FE games have this issue; they're either stand-alones or sequels, or in the case of the first Fire Emblem Warriors, simply incorporate characters from other games. Three Hopes has mostly the same cast as Three Houses but at the start of the game they encounter Shez the avatar/main character of Three Hopes instead of Byleth, the avatar/main character of Three Houses and this radically alters the course of events.

(And sorry I haven't watched any of the stuff from the new Star Treks so I have no idea if it's similar.)