Something else, I noticed that on the apploader from the website, agps offers to download datas from different kinds of sattelites, whereas in the gadgetbridge app, it doesn't offer the sattelites, but just data for different durations.
What you describe is the difference between Bangle.js 1 and Bangle.js 2.
For Bangle.js 1 different time periods are offered, for Bangle.js 2 only the satellite settings.
The data are not compatible with each other, but they are uploaded without error message.
Maybe the apploader in the gadgetbridge app recognized your Bangle.js incorrectly?