Doesn't matter at all what he will be like in 2028, if Biden wins the entirety of the following 4 years should be spent by the Dem's looking for a viable candidate because I don't think they currently have one who will be accepted. Biden is a null factor in 2028 because he will have had his 2 terms and can't run again. The only candidate I have seen suggested to seriously replace Biden is Michigan Governor Whitman Gretchen, do you think America is ready for a female President? Will they accept a female President?
The biggest problem in this entire debacle is in fact the media, and Trump may be right in that they are the enemy of the people, oh but not in the way he means, they simply don't have the good of the people in mind, it's about numbers to them and nothing more. Every minor misstep Biden makes is hugely inflated and appears on the front page of every major media site, major blunders by Trump are glossed over and quickly forgotten, because they no longer make the news or attract readers, I mean they hardly bother fact checking him anymore, fact is nearly every single thing Trump said during the debate was a lie, yet all we hear about is Biden being a bit under the weather, a bit slower than he normally is. Blunders by Trump have been so common and so regular they simply aren't news anymore, they aren't worth reporting because everyone know he makes them, blunders by Biden, well yes they are news because he is President.
How this will play out in the end who knows, but it will be bad news if Trump wins.