With the pot now on the bottom facing up, the pulling force transferred directly to the metal pot case instead of the plastic, steering wasn't as smooth as before. PLA is good at chewing up metal so this idea might be short lived.
The leading idea is a big old PLA bushing covering the entire pot until a small part of the end. Then a TPU sock grabs the end of it. The TPU sock flexes on 1 axis.
Easier designed than printed. It would require a separately glued horizontal piece.
The next idea is the pot going in a TPU sock between 2 outer bushings, where it wouldn't experience any loads. This would make the enclosure a lot bigger. The pot, the sock & all the wiring would be down where the spool is. The sock could be attached by magnets.
There's a simulation of the pot & sock crammed in without enough room for the wires. The spool definitely needs to move farther away.
Another idea is not sensing the steering with the entire spool, instead having the spool pivot on load bearing bushings for only pitch. The steering angle would be sensed by a non load bearing thing.
It was noted that going too fast always makes it spin out. It swerves 1 way until the force of the leash pulls it the other way. The only way to recover it is to retract the leash. You wouldn't want it to spin out on the narrow path. Maximum speed could be reduced by yet another parameter, but you want a faster maximum speed on gravel.
There's always the case of a dead battery leading to pulling it.
It might be over complicated. If it just sensed steering & relied on the animal pulling it for traction, it would eliminate the spool, the encoder, the spinouts. It would take a heavier leash & probably more space.