Gboard (available here) works just fine for Esperanto. Those who say Esperanto is not available are incorrect. Go to: Settings > System > Languages & input (Gboard) > Virtual keyboard > Gboard > Languages > Add keyboard > Esperanto > Done. (Tested in Android 10).
When you get to Languages & input (Gboard), avoid the temptation to go to Languages > Add language, because Esperanto is not on the list there.
AnySoftKeyboard no longer supports an Esperanto keyboard layout, but the accented letters are still available via a long press on the host letter on its English keyboard.