Orbit and Gravity Movement Blueprint

Having a pawn walk along a sphere is not supported by this plugin because the gravity direction of skeletal meshes requires engine code changes to make walking physics work correctly. You can use this plugin to give PlayerPawn’s an orbit and be affected by gravity, but they will not be able to walk along a sphere.

This plugin may be what you are looking for: Directional & Planet Gravity in Code Plugins - UE Marketplace. You could possibly combine these two plugins together but I haven’t experimented with that myself yet.