The older one was the original and whoever created it did most of the work and should be blessed by the heavens.
The newer one took the older one, and replaced the screenshots of code with markdown equivalents so they could be rendered by Anki while saving memory. You can see this in the difference in the number of images between the two decks. This is the one I'd download and use.
I love Andy Matuschak! His podcast with Dwarkesh was so enlightening and his blog is great as well. He's one of those people whose work I go back and read every couple of months and I always learn something new