iirc, it costs $99 a year to be able to upload apps on the apple app store rather than a one-time $25 on android. Also, apple test flight or whatever has a limited amount of people who can use it, rather than just installing an apk on android. Apple’s ecosystem makes it much harder for open source or small apps to exist for iOS devices.
If you want collaspable vertical tabs, you should look at using sideberry & this userChrome.css file set: https://github.com/Redundakitties/colorful-minimalist/tree/main