Hi, baytril or enrofloxcin is not used to treat psittacosis. Doxycycline is used.
CBC is a complete blood count, it's a great tool, but is not a test for diseases, you would need a culture, or spevific serology to test for psittacosis or other diseases.
A culture would be very important to determine what type of bacteria or yeast or fungus is causing the Infection. Other tests would be needed if virus are being tested for.
Was a culture done? Was a specific tests sent out for?
I'm sure a vet doesn't want to hear some chic on the internet is diagnosing your bird. And I am not. Only a avain vet who actually sees your bird and runs tests can do that. I'm just advising you, and giving you Info.
And the previous advice on sunshine, probiotics and cleaning the cage extra well will help a d is good practice anyway. I'm attaching another link
I do hope cultures were done, since this infection has persistent, and that a real psittacosis test was done.
https://www.thesprucepets.com/parrot-fever-psittacosis-symptoms-treatment-4148338
I hope also you will offer leafy greens, broccoli, veggies like cooked sweet potato, and offer peppers these will provide vitamin A, and most parrots are willing to nibble on them, sometimes even the first time you offer.