On the SMARTDAC+ Paperless Recorders GX/GP models with the Advanced Security function (/AS), is it possible to switch screens or scroll back through trend graphs while Logging Out?

Yes, by turning on Operation on Logging Out.
Even if you are logging out, in addition to logging in, you can switch the Operation Display and scroll through trends. The setting method is as follows.

On the main unit, press Menu, and then select:
MENU key > Browse tab > Setting > Setting menu Security settings > Basic settings > Operation without Login