Keep in mind that you are the world’s foremost expert in you!
Diagnosis is less important than your treatment success. If you agree with the psychiatrist on diagnosis but still have a good relationship with the PsyD, then work through your situations without regard of diagnosis. Diagnosis is just a label so a treatment approach can be started. Work with both docs and continue to be the expert on you and find what works for you, not what others think you need. Be clear with both docs on what works and doesn’t. If that puts a strain on your relationship with either the psychiatrist or psychologist, then you should find a new one.