I'll share but these are not necessarily strong recommendations haha—many of these decisions stemmed from what I used in the last few years as a full-stack eng at Pinterest, and being able to move quickly came from muscle memory from using these dev environments.
iOS - Objective C, UIKit, IGListKit
web - React on next.js and native css
Android - Kotlin
iOS - Objective C, UIKit, IGListKit web - React on next.js and native css Android - Kotlin