Gadgetbridge allows automatic SQLite database export to the location you specify.
Navigate to Settings -> Automations -> Auto export database, and from there you can configure the details.
You can put it into a shared Syncthing folder, or something alike, or process it with Termux + Tasker. Personally, I hesitate to send megabytes of data over the wire every couple of minutes, so I rigged up a script that extracts the required metrics (for now its my steps only, the rest does not seem to be accurate) and sends a payload to my queue, where a consumer script later adds it to the DB.
rcmd
joined 3 days ago
FTR: currently experimenting with scraping Gadgetbridge data into Grafana.

To my knowledge not really much is available. You may use an intent to trigger database export and then use SQLite to scrape data.
Also keep in mind that data is kept in device specific tables.
https://codeberg.org/Freeyourgadget/Gadgetbridge/wiki/Intent-API