The promised ARA2 would be fully implemented in a maintenance fix for Cubase 10.0, then they settled for making us render the tracks first and then use Melodyne, so that you may as well use the VST version instead.
Now, they have completely stopped on fixing ARA to be useful. The latest 10.5 maintenance fix contained nothing about ARA.
It is really annoying, because Melodyne 5 rocks, so having to deal with Cubase’s buggy implementation sucks, but I guess more color options is more important.