Josh Morony’s blogs have helped me a lot too - even though some may be old
Besides angularfire, I have found the firebase docs very good
Jave did not mention his own goodies which are very useful too https://jsmobiledev.com/
U may want to study NX by Nrwl before starting. This may boost productivity a lot. Josh has some nice Youtube videos on it
And u may want to understand importance of state management - not sure how that is done in Xamarin, but a common pitfall for some. Josh also touches this which can serve very well as introduction
And the Tour of Heroes example is mandatory learning (angular.io) 