For 1.20/1.20.1, you cannot have unknown data in a data pack or else Minecraft will refuse to reload any loaded packs. This is classified as intended game behavior. As such, you will have to remove anything in this folder that doesn't relate to a mod you've installed.

For example, this pack supports The Aether on 1.20.1. If you're using this data pack on 1.20/1.20.1 and do not have The Aether installed, you must remove the "aether" folder from this folder.

If you're playing vanilla, remove everything in this folder EXCEPT "minecraft".

Here's a list of the folder names and what the mod names are for reference:

advancednetherite					Advanced Netherite
aether								The Aether
cataclysm							L_Ender's Cataclysm
create								Create
farmersdelight						Farmer's Delight
irons_spellbooks					Iron's Spells 'n Spellbooks
mekanismtools						Mekanism Tools
netherite_plus						Netherite Plus
netherite_shulkers					Netherite Shulkers Reforged
netheritehorsearmor					Netherite Horse Armor CJ
quark								Quark
shieldexp							Shield Expansion
simplyswords						Simply Swords
sophisticatedbackpacks				Sophisticated Backpacks
travelersbackpack					Traveler's Backpack

Thanks to my buddy Singing_Steel for bringing this to my attention, because I didn't think to test this.