I agree, but then again, I've known a few Democrats who were low info voters that were "interested" in RFK. Meaning non-partisan Dems that just aren't happy with the status quo. I'd say he pulls 70% from Trump, but possibly up to 30% from Biden. Think Ross Perot in 1992 except more lopsided.
60-40 is my split, but I definitely agree that he’ll ultimately hurt Trump more than Biden.