Any experts on electrophoretic lacquer here? Need some help in sourcing a high quality lacquer.

Need to apply lacquer on a mild steel product that is zinc plated and has some vibratory surface polishing on top of it, which wears the zinc down a bit.

Need to pass 500 hours on a British Standard salt spray test (BS EN ISO 9227: 2017)

If anyone has any sources on a good lacquer supplier please let me know. Tried one by LVH coatings but it didn't pass more than 300 hours.