It's more than tapes. It's huge sums of money that he owes Putin in the form of "loans" for his real estate ventures.

You are right though, Trump fell into Putin's lap and we will be unwinding the damage for decades. Who knows what keys he gave Putin? Also, when people ask why people act like they are nuts (I'm talking about Qanon and the GOP), disinformation campaigns can be highly effective and especially if you have a whole television, Facebook, Twitter ecosystem to feed back those lies over and over and over until they believe:

WAR IS PEACE

FREEDOM IS SLAVERY

IGNORANCE IS STRENGTH