This sounds like a pretty awesome idea.

I like that you’re thinking about privacy.

This app is great and only gives milestones on specific tours they choose, it might be a good thing to look at for inspiration. Maybe give milestones for the public info? You also have the option of turning it off: https://www.theconqueror.events/all-challenges/

I use Strava, and overall I am happy with it but for the lack of one feature that really bugs me - it has no option to set it up to do a one button start. Currently to record a ride or other activity I have to press record, then press Start - which doesnt always start recording.

Having the ability to set your app to do one touch activity recording would be a feature Strave does not have and therefore an advantage