If Valkyrie is in Endgame, she’d probably connect with Thor at some point.
Chris Hemsworth may be on that boat, although he has said he’d be happy to return as Thor whenever they need him.
Avengers: Endgame isn’t quite the end of MCU Phase 3, as we initially thought, but it does seem to mark the endgames for some original stars and their characters.
I have been avoiding any spoilers, so all speculation is valid to me.