Even if it is way too early, Trump seems a real DOA against Biden (and to some extend Sanders), but all other races seems winnable (EV). There is 15% undesided and a reasonable (IMHO) assumptions that they will break more towards Trump when election is near enough.
Also, if Biden keep these numbers, it will help him greatly during the primaries.
Why would you assume that undecideds will break more towards an unpopular incumbent? The opposite seems more likely. I'm not saying it can't happen that way, but am curious as to your reasoning for the assumption.
