By request, I've done a brief review/overview of the excellent third party Mastodon app @Tusky for Android:
➡️ https://fedi.tips/tusky-for-android/
It has lots of stuff missing from official Mastodon such as draft posts, post scheduling, custom timelines etc.
Hopefully this overview is accurate, do let me know if you spot mistakes.
Overall, it's a really solid app packed with features and an easy to use interface, anyone with an Android device should try it. Recommended 👍