Please look at this that might help with the problem of DPF in Kubota.
https://www.wickhamtractor.com/blog-posts/how-to-reset-kubota-error-codes/#:~:text=But%20is%20it%20possible%20to,be%20gone%20after%20this%20step.
https://4dpf.com/kits/kubota-dpf-delete-kit/
Good luck.