The TNT tiktok shit, in its entirety, couldn't have taken more than like three days to edit. Getting the script takes read and playing through the extremely boring WAD would've been the bulk of the time dump, and even then I can't see the entire project taking more than a week if you could dedicate to it full-time.
It's filler, Hexen 2 is filler, but if he's banking on youtube/patreon as a primary form of income, you've got to shit out filler even if you're working on something with a bit more juice to it.