@jaki101 Glad to hear you are seeing a different Cardiologist. Who will depend on your insurance (do you need to stay within a certain network?).
1) In the last four years I have seen many specialists and I have learned an important lesson: Specialists have subspecialties! One cannot and should not depend on one Specialist knowing and being able to treat all conditions in their Specialty.
2) All your medical tests and your doctor's Notes are available online BY LAW. The Cardiologist's office should help you set up your "MyChart account" and then you can read everything they have about you. Maybe your parents do this since you are under 18.
3) ChatGPT and Google Gemini (to name a few AI sites) can give one a lot of information on tests and Doctor Notes. They can make mistakes, so one should talk to Doctor also but still they provide a lot of information. I put all my tests and ask for interpretation, and I also give it my Doctor's Notes to get an "interpretation"
3) Pulmonary Hypertension is a significant health issue and it can have a variety of causes so the right specialist will depend on the cause. In my case, my lung conditions are causing it, so I see a Pulmonologist specializing in interstitial lung diseases. Best wishes and remember to just keep putting one foot in front of the other.