But the author needs to get money to pay for the work somehow. If you don't want to give them $$, then you need to give them something else like advertising revenue. I assume Stravas business model is advertising and critical mass - Strava premium has value because everyone else is on Strava .
Any half decent app will take a dozens (or realistically hundreds or thousands) of hours of work to produce (at least twice, for Android and Apple), publish and maintain. Anything involving persistent data will also require some kind of host, storage and backup.
If it's using mapping, it almost certainly needs someone to pay for access to the maps, too.
That simple idea, which is essentially Strava segments, will cost someone at least $1000/year to provide to you for free.
If you want a free way to track segments, then just stick with Strava and look at them after the ride.