I had the same frustration with the lack of mobile support. Recently, I figured out a way to insert citations by typing @ and searching by title or citekey, which works on the mobile apps. It’s powered by the Various Complements plugin, using a custom dictionary converted from a bibtex bibliography.
I’ve shared the script that handles the conversion here, along with a setup guide: Mobile citation autocompletion guide using Quickadd and Various Complements
This does not cover creating literature notes, though.