I don't think Onana's problem is that he gets caught in two minds.
There's a saying (kind of) in footy schools that goes something like this: Excellent goalkeepers can react even under the toughest of circumstances. This often allows them to make saves very few people expect them to make. Great goalkeepers, on the other hand, read and then react. This removes the need to produce miraculous saves regularly. The former usually play within their strengths and the defence adjusts to them, while the latter are an active part of the defensive line. Constantly shouting instructions, guiding their teammates, reading the game and anticipating where the danger in the box is most probably to occur etc. It's not all black and white, of course, but United have had success with both types.
The problem with Onana, thus far, is that he's neither reading nor reacting. He's guessing... Often times, he's rush when he has time and indecisive when he hasn't. Whether this is a confidence issue or something else, i don't know. Henderson, for example, was beyond confident. He was arrogant and believed (believes?) that he's a much better keeper than he actually is. I think it was the opposite for Wolves' equalizer. I believe Onana was too afraid that he wouldn't be able to make a save at his far post. He had already made up his mind on that, thus opening up an opportunity for Neto that shouldn't be there.