ok this may look like a lazy ass beginner crying out for spoon feeding( which it kinda is), but i want some real industrial training in non documented Android coding.

For last 2 years i have been reading tons of Android articles and documentation on "how to use this library", "how to add this feature", "what this function of this class does", but not much about how to use it efficiently, like the way its used in industry.

When I interned with a startup, all they wanted from me was to push new design changes, fix layout bugs and work as fastly as i could. I had no time to understand their core code, which had so many things that i could have learned : those mvp/mvvm design/architecture patterns, dependency injections, kotlin , coroutines, state management designs, data bindings, eventbuses and handling, and VIPER,RIBS (I mean, not everything was particularly in their code, i picked up a few keywords from here n there)... a lot of stuff that is used by many apps for their codebase.
I can read up these stuff by myself, but i always end up feeling bored coz frankly, i got no big/valuable project to implement it upon and feel excited about it. I feel that open source projects from OSS companies could be my window, but their chat spaces are also mostly empty to discuss/get some guidance.

I want some specific training about these. Can you guys provide any online/offline course/company training/books in this subject, the best practices?

I love most trends around js, because often they're thoroughly thought through (not always) and make things easier.. but why the fucking fuck do all the js coding standards use 2 SPACES. Now this isn't intended to be a tabs-vs-spaces rampage rant. But this decision against tabs is like saying yes to a 50ct pencil instead of 100 dollars.