Originally Posted by
JohnJ80
This has the most options, but you also have to donate as far as I know.
I'd make a list of what ones you want to connect and start looking at your options.
Garmin Connect will export automatically to quite a few, along with the Wahoo Fitness app.
Certain APIs can't talk with other APIs, but I believe tapiriik gets around this so you don't have to manually upload.