Hmmm, I was about to say well fortunately there is , even if not very convenient: in the Freeflight App, navigate to your flight history and from the top right corner you can request the flight data to be send via email. But I just checked and tried but wasn't successful. Last time it worked for me was on 29th dec 2023.
I just tried sending my flight data to my email and it worked fine. (an older flight that was in memory)
flightdatamanager can import that file and use it.
Confirmed, when I tried with older flights (before 1st may) it worked for me as well. However I have 2 flights in my history on 1st may, which it will not send for some reason ...