When I woke up this morning I saw the headline and I thought "here we go again". I watched the video and my impression is that he said that sentence in his classic dementia rambling, right after it he said "he should have ended it".
Basically he was blaming Zelensky for not having negotiated right away and Biden for not having pushed for it.
Not sure if this makes it any better, but at least I got the impression he mispoke saying that particular thing.