Biden has never been likable. He has always been an arrogant, mean, vindictive, malicious, corrupt, unintelligent individual. It's possible some of these qualities have become more pronounced with age and the effects of his two brain aneurysms, but the younger Biden was not too much different than the man he is today.
By the way, he turns 80 on 11/20/22 so his behavior is likely to get worse as the months go by. I'm not qualified to say definitively that he has dementia, but except for an obvious creakiness in him, Biden has always been this nasty and aggressive. I think the main difference between the younger Biden and today's version is that he is no longer capable of hiding his true self in public.
He has always been an arrogant, mean, vindictive, malicious, corrupt, unintelligent individual.
In other words, a typical Democrat.