I just by chance did a /reload on my datapacks, and got some issues related to snuffles on chat and latest.log.

Here's the gist with the relevant lines: https://gist.github.com/vico93/22558e865e4e7b44906dfcc40705eb75

After installing CompatDatapacks i realized those errors are caused because the data content of the mod is still on 1.20.6- format (1.21+ changed some folder names from plural to singular).

I really hope a correction of this (and a proper update to 1.21.1) are in the plans @Suel-ki