Each Executive Order has a number for reference. No such number is given as proof of this claim of legality. This group of lawyers thinks we should believe them because they say so? Horse puckey. Prove your assertions.
13292
13526
This does give a V.P. classification and declassification authority, but it looks like only if V.P. is the originator of the work.
It also lays out a timeline for some items to be declassified automatically if they meet certain criteria (which may apply to DJT as well as Biden).
I have to admit, it’s a bit long and I didn’t read it thoroughly.
This doesn’t excuse the fact that classified or not, Presidential records are supposed to be placed in the custody of NARA at the close of every administration.