They are going to have Thor want to go off with on an adventure with the Guardians, and Eitri reforge a version of Mjolnir to leave a Thunder God/Protector on Earth. New Mjolnir get put in New Asgard to find whomever is worthy ala Captain America, with his wielding the old hammer giving Thor the idea so he can leave. Jane is in some observatory in Norway, and comes to visit for some reason after many failed attempts by others and picks up the hammer. Maybe she finds out she has cancer and goes to see if Asgardian medicine can help? Walks into the Hammer room, pulls the sword from the stone, I mean picks up the hammer and BAM, grrl pwr!.
Movie is Jane and Tessa Thompson fighting whatever Thor villian dejour, getting together, with Chris Hemworth bookending to join the Cosmic Marvel Universe and make way for Jane. "Who is she?" "Well, when I'm not here, she's Thor". Marvel pats itself on the back and rolls credits. Not the MCU we need but the MCU Disney Marvel thinks we deserve and will pay for.