Trumps lawyers are telling us they have no defense in the secret document investigation.

[FBaggins]

39. How credible is it? Not very

Unfortunately, legal defenses don't have to be particularly credible in order to prevail. They merely have to introduce a reasonable amount of doubt in one out of twelve jurors.

But that doesn't really address the hypothetical. In that imagined story, Biden has not created any record (other than the fact that he talked about it on television). Yet we couldn't really claim that he had broken the law. Classification standards exist to get the President the information necessary to make decisions. What they chose to do with them may be stupid (and even impeachable), but "illegal" is a much tougher standard to apply.

Isn't it still against the law to remove documents from the WH whether classified or not?

No. That's definitely not the case. That has been the oversimplified shorthand description of the Presidential Records Act... but that isn't what it says.