Can Pitra Dosh be fully removed permanently?

Yes. Pitra Dosh is a condition caused by unfulfilled ancestral debt and conditions can be remedied. The Garuda Purana and Brahma Purana both specify that Shraddha, Pind Daan, Tarpan, and where required Narayan Bali or Tripindi Shradh resolve the Dosh by nourishing the departed soul and enabling its progression from Preta Yoni. Permanent resolution also requires establishing a regular Shraddha practice going forward to prevent fresh accumulation of ancestral debt.