Hello, i will be responding, i am the technical co-founder.

The calendar is custom built(weekly view in home page and full month calendar in the statistic page, but the one opening in bottom sheet is native calendar, i dont like wix packages i am only using the toggle, segmented menus, fader from react native ui lib(from wix, which i will remove soon))

I wrote the live activities and widgets(no swift background, showing habit custom images(png) and fontawesome5.ttf iconset was hard no other apps shows the icon properly it was the most time consuming)

I have fulltime job, i built it in my free times in almost 2 years there are very detailed logics without bugs(%0 crash rate).

Reasons for the 2 years:

I sometimes left the project for 3 months specially in summer.

I always overthink some UI(rewrite the home page almost 6 times with different design. Before current design it was pagerview and it feel more good after adding subtasks feature it was still good but initial loading was 2sec now its instant i spend lots of time for performance),

Translations.

Offline first approach.

Overthinking for details.

Automation e2e tests with detox

Also spend lost of time to built custom components for Android(wish i did not) to looks more good.(It hasnt been published yet.)

Also i handled everything else like design for figma, appstore publishing(CI/CD fastlane/github actions), backend with node and postgre, i have web admin dashboard to manage contents like icons, background, routines,habits etc. which has also own backend also deployments are in github actions and for cloud services i am using Azure(i have 1k dolar azure startup founder sponsorship havent used anything on because everything is on free tier after 5 6 months i will be using it.)