I think you've done all the right things
Ferplast wheel looks fine. The silent runner will be gentler on his feet if they're sore, so that's a good move. The ridges on the Ferplast one might aggravate a bit possibly, but I'm sure it's fine for now.
How old is he again? Yes it can be another pressure finding an exotic vet, so maybe just see how he goes and have that as a plan B. Do you have a photo of his feet? Some people on here are quite good with medical/health matters.