Possibly. But I would assume that paper was somewhat expensive in the 1400's and so it's unlikely to be a notepad of doodles.

For all we know some ne'er-do-well made it, or commissioned it, to use it to defraud someone with far more wealth by one means or another "hey I've got this manuscript of this far off land, it is rich with treasure and fine goods, give me money to go there!" or "hey look at this awesome alchemical text, you know you want the prestige of owning this!" or some such.

It could even just be "hey, I'm your patron, make me something really weird to show my kid". I've always suspected it was just some odd art piece... I mean... comic books and science fiction don't have to be unique to modern times.

Maybe it’s just me, but I find all of the “maybe it’s just a _____” explanations are still really fascinating each in their own way.

No I feel the same, if this was just some random art commission or something it would still be an incredibly interesting piece (and story).