Here is a better article about this change: https://www.dcrainmaker.com/2024/11/stravas-changes-to-kill-off-apps.html
Here is the precise line that sucks: “You may not process or disclose Strava Data, even publicly viewable Strava Data, including in an aggregated or de-identified manner, for the purposes of, including but not limited to, analytics, analyses, customer insights generation, and products or services improvements. Strava Data may not be combined with other customer data, for these or any other purposes."
Worth noting that I’m sure your plan is “up to 1000mbps”. They always use the words “up to”. The speed you are paying for is the maximum you can get, not the minimum that they guarantee you will get.