Trump has no clue how to debate, All he does is yell and talk over the other person with false statements and stupid remarks.
Debating really has no similarity to what is needed to govern a country, which requires choosing good advisors and listening to them, rather than firing them and calling them mean names. Biden has experience in government, Trump has none and refuses to even try to learn how to govern.
Debating is not really important, but Biden knows how to debate and all Trump knows how to do is be rude and yell and throw childish tantrums.
No presidential debate has followed the rules for debating, by the way.