We have unity in teaching we know where the target is and there is one authority
Yes, there is unity in what the Roman Catholic Church teaches, including all the particular churches in communion with her. But the same can be said of just about any given Church. The Church of Norway, for instance, also have unity in teaching on this level. The teaching is found in her confessions and creeds, in her liturgy, and her Canon Law. And she is governed by her bishops.
The problem is that you seem to compare one ecclesial communion (the Roman Catholic Church, including all the particular churches in communion with her) with a whole bunch of different communions who have never claimed to be united. That is a bit like saying that England is better than Europe because in England there is only one set of laws. But England is a nation, Europe is not. With that kind of tactic you will, of course, find disunity.
I, for instance, who am a priest in the Church of Norway, am not in unity with, say, baptists. But we have never claimed to be, either. Just as you, who are a member of the Roman Catholic Church, are not in unity with, say, pentecostals. But then again you have never claimed to be.
What you need to do, however, is to take each Church separately. And you need to take the teaching of each Church, not what anyone there personally believes at any given moment, including bishops and priests. I bet you will find Roman Catholic bishops and priests who hold personal beliefs which are contrary to their Church’s teaching, yet this doesn’t constitute proof of disunity. If that is so, it cannot constitute proof of disunity in other communions either.
So this is not a ‘Protestant’ problem, whatever that means.
Note that when I say ‘communions’ I means particular churches or ‘collections’ of particular churches which are in full communion.