You probably just need to go to a few more locations in the Heimdall or Hel quest line. If you are not getting new quests, go back to Valhalla and Fjordheim to see if a quest giver has been missed.
Journal Quest III - "Where to Next?" - (At least 9 out of 12 needed)
Frigga - Langobard Village, 1 page, https://ibb.co/LrnV1dg
Frigga - Odin's Bedroom, 1 page, https://ibb.co/9v6Z4mr
Frigga - Mistletoe Forest, 1 page, https://ibb.co/r6DPjDP
Frigga - Slimy Lair, 1 page, https://ibb.co/CnZW4nt
Heimdall - Deep Mines, 1 page, https://ibb.co/6J3gn27
Heimdall - Icy Asylum, 1 page, https://ibb.co/yYvgcwG
Heimdall - Broken Bifrost, 1 page, https://ibb.co/QmwFzKm
Heimdall - Heimdall's Hideout, 1 page, https://ibb.co/3dkvD82
Hel - Highway to Hel, 1 page, https://ibb.co/3WhbXs8
Hel - Sickly Hollow, 1 page, https://ibb.co/qYftxXd
Hel - Baldr's Gate, 1 page, https://ibb.co/99cL2Dp
Hel - Odin's Feast Hall, 1 page, https://ibb.co/nMq54nP
To find Valhalla:
On PC/Web, you cannot open Valhalla from a god map or the Father map. Go back to the Map Manager page for Scandinavia. Click on the "Main button." Valhalla is the tall ice mountain near the top of the Main Scandinavia map.
On Mobile: Swipe back to the Thor quest line. Valhalla is the location with large metal circle around it.