Please make sure that the saplings of rubber do not grow from 1 time when using bone meal. To grow any tree in minecraft, you need to poke a seedling with bone meal several times, thus bone meal for trees will be costly, and to get a rubber tree - only 1 flour is needed, this is an imbalance.

Let's respect the mechanics of minecraft, on the version on which we play 1.19.2

this was intentionally this way in all versions of ic2 classic and I can tell you without even asking Speiger, that this won't change anytime soon