The internal polling is actually far worse for them than what they admit to here. Since the debates New Jersey, New Mexico, Minnesota, and New York, all of which are typically very blue have become toss-up states. I can only imagine since the attempted assassination that Trump's lead has only gotten bigger.
This guy has been doing pretty good analysis and coverage of the polling for months. Granted these are just opinion polls which should always be taken with a grain of salt, but nevertheless the propaganda of the past few months that have been trying to portray the race as close have just been bald-faced lies, Biden has been down both before the debate and especially after it.