To Withings defense: At least to my experience they have the most open API going on: https://developer.withings.com/
Other players in the field like Garmin are super restricted.
For my own use case i swapped to Health Connect (Android) though. Whatever might happen with that.
Of course i am also appalled about this change and also the pretty much non-response from the customer service in the forum about this, no good arguments have been mentioned.