Best front end/back end for gym/diet/sleep/journal tracker desktop app?

Want to make a software to track gym/diet/sleep/journal all in one that is desktop based like windows and in the future connect it with phones like iPhone. Mostly focusing on the desktop version right now. Could also make a web version too in the future.

I have python but don’t know if that’s modern and will make this program polished the way I want it to be. I’m looking to really make the best of all these apps that does diet/sleep/gym/journal apps because they’re so unintuitive and too many apps are annoying to use and want to put it all into one app and program.

Ty.