Coding an app for running and cycling ?

Hello everyone, I don’t code and therefore, I speak out about what I miss, in case some of you would consider coding it. I’ll speak about running and cycling, ‘cause with a HRM and a gps, that looks like a logical usecase.
I usually run with an old Garmin watch that does the trick pretty well, but rather than copying this design, why not make something better ?
Ideally, it’s an app that would record in the background a .gpx or .fit or else with the gps, HR, speed and all relevant infos that can be used in another app (like GoldenCheetah, Zombietracker gps on Linux, or Forrunner or Opentrack on Android). While exercising, it’s great to have some live infos displayed : HR, speed, distance, elapsed time. 4 different infos, one in each corner, in a colored square. I attached a drawing I made, just to have a rough idea about it. In an ideal world, taping the HR corner would alternate between BPM and « zones »*. taping on the speed would alternate between km/h and pace (time per kilometer). Taping on distance would bring average pace so far.

*Heart rate zones are calculated depending on a percentage of your maximum heart rate. It’s a useful tool, very appreciated amongst runners to simply check if you’re pushing too much.
Zone 1: Easy – 68% to 73% of max HR.
Zone 2: Steady – 73% to 80% of max HR.
Zone 3: Moderately Hard – 80% to 87% of max HR.
Zone 4: Hard – 87% to 93% of max HR.
Zone 5: Very Hard – 93-100% of max HR.

To finish the activity, a click on the side button could bring a menu with the option to 1) pause/resume the recording, 2) discard or record the data 3) Have an overview of the race (average speed, average HR, distance, time elapsed.

In the settings, it’s important to offer kms and miles.
I finished my wishlist for Christmas next year !

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