WheeledVehicle floats and doesn't move

I’m trying to use a custom model made in Blender with a WheeledVehicle blueprint in UE4.26. I followed the Documentation’s Vehicle Art Guide and Vehicle User Guide but was having a problem where the car falling to the ground with no wheel collision and not moving. I solved this by properly scaling the car skeleton as suggested in a Discord message.

The car uses the same names and basic setup as the example dune buggy car, with a PhysWheel and VisWheel bones, and only the latter is connected to the mesh while the former isn’t:

The VisWheel copies the position and rotation from PhysWheel in the AnimBlueprint (again, like the example dune buggy):

However, the car simply isn’t affected by gravity at all and does not move:
You can see the wheels spinning here, meaning the PhysWheel bone is being properly used, and the car is receiving input, but doesn’t move.

Gravity and Simulate Physics are both enabled and the Physics Asset is setup according to the Vehicle Art Setup page:

Can someone help me with this? Thanks.