See gh-28212
Comment From: bclozel
See gh-28210 - a similar PR has been rejected (at least for the RxJava3 part).
As for the removal of deprecated RxJava managed dependencies, this is something that we'll probably handle in due course when the main branch switches to 3.0.x.
Comment From: avillalain
@bclozel thanks for letting me know. Also is gitter the best way to reach out in order to find what good issues are there for a first timer and to coordinate?