I don't think Biden did that bad. Sure he slipped up once or twice but he answered every question with a relevant policy that he implemented as well as bringing up what they were trying to do next. He was able to speak clearly and reasonably.
Trumps response to questions was to dodge and lie. I don't know how anyone can walk away thinking both sides were equal or worse that trump "won".
When I see posts saying Biden was a bumbling idiot in the debate I wonder if the person even watched the debate.