Cloo
Banana for scale
I'd had similar feedback to that; a mixture of nerves and my naturally rambly manner.
But being told that I rambled and was unfocussed is not helpful, because that is just nerves!
But what I did in response to that was to literally practise key points keeping on topic. It felt quite weird, and given I had three interviews for the role I have now, did get quite repetitive. But it definitely helped; I could 'tick off' covering key points as I went along.