Firstly, I want to say a huge thank you for developing this app. From its user interface to privacy - it truly is excellent Masha’Allāh!
However, I do have one suggestion which I believe would be an excellent implementation to the app.
I live in London, and many Masjids use the London Unified Prayer times established with East London Mosque.
Please find below where you can find the API they use:
It would be absolutely brilliant if you could add this to your selection of calculation methods.
May Allāh ﷻ bless the Pillars team.