Thank you for mentioning Gadgetbridge, here are correct URLs for the project:
Repository: Freeyourgadget/Gadgetbridge: A free and cloudless replacement for your gadget vendors' closed source Android applications. See the list for supported devices. - Gadgetbridge - Codeberg.org
Homepage: https://gadgetbridge.org/
Gadgetbridge ensures your data remains private and local. We are looking for developers, feel welcome to improve what you think can be made better.