Traveling to Budapest in 2 weeks

I would like to ask my fellow group members  to learn if any of you are, will have, or was in a similar situation to mine. I am fully vaccinated (2x Pfizer) administered by UCLA in Santa Monica,California. Born and raised in Budapest, Hungary but I'm not a dual citizen. US Citizen only. I recently bought my flight ticket through United Airlines who allows passengers to upload their Vaccination Certificate online -which I did. The purpose of my travel is a business trip and I do have all the necessary acceptable documents to prove my purpose of traveling to Hungary. My one and only concern/worry is the so-called "PCR" Test. The concern is based on the fact that my US Covid-19 Fully Vaccinated Certificate is not recognized in Europe. My reservation (Flight +hotel) seamlessly went through online with priceline and my Airline Company is United Airlines. The trip will take me from LAX to Denver Intl. Airport to Frankfurt, Germany Intl. Airport. From there Lufthansa takes over to fly me to Budapest, Hungary (Liszt Ferenc Intl. Airport), which is my final destination. Here comes the concern: The PCR Test. My friend advised me to get in touch with United Airlines to get answers to my question about the PCR Test. I would like to know if any of you here experienced -went through - similar situation and if yes how was it? Thank you very much in advance.

USA Travelers are now allowed into the EU, Get tested and bring the results with you.

Hi! Can you please explain this to me in a little more in details...? I am planning to give a call to United Airlines since  my entire reservation was made and completed through them (United). Thank you very much for your time. So I must produce a negative test results even though I am fully vaccinated with Pfizer. Let's say I leave on July 1st from LAX Int' Airport. Where can I get a PCR Test? At the LAX Airport?
I apologize but this is so new to me and also can be very confusing, as well.

Each country and airlines have different rules so yes it is very confusing. Your airline should be able to tell you the updated info as things have changed on a daily basis.

I think you should ask your airline and they will guide you better, but as far as I know, these days Most airlines not allow to board anyone without Negative PCR, But I will again suggest you ask Your airline.

How did the trip go?
I am all worried that I accepted the sputnic shot. I didn't think that I go to US than. But It turned out that I go in about September. However, if the Pcr test is a must, than doesn't it matter which vaccinations people have?