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:

aquaculture					Aquaculture 2
aquamirae					Aquamirae
aquamirae_delight			Aquamirae Delight
autumnity					Autumnity
beachparty					[Let's Do] Beachparty
biomesoplenty				Biomes O' Plenty
biomeswevegone				Oh The Biomes We've Gone
bloomingnature				[Let's Do] Blooming Nature
blue_skies					Blue Skies
born_in_chaos_v1			Born in Chaos
brewinandchewin				Brewin' and Chewin'
camping						[Let's Do] Camping
cataclysm					L_Ender's Cataclysm
cobblemon					Cobblemon
cold_sweat					Cold Sweat
create						Create
createfood					Create: Food
croptopia					Croptopia
darkerdepths				Darker Depths
dungeonsdelight				Dungeon's Delight
farmersdelight				Farmer's Delight
farmers_spell				Farmer's Spell 'n Spell Book
ecologics					Ecologics
gardentrails				Garden Trails
herbalbrews					[Let's Do] Herbal Brews
hybrid_aquatic				Hybrid Aquatic
iceandfire					Ice and Fire: Dragons
irons_spellbooks			Iron's Spells 'n Spellbooks
legendary_monsters			Legendary Monsters
legendarysurvivaloverhaul	Legendary Survival Overhaul
magistuarmory				Epic Knights: Shields, Armor and Weapons
meadow						[Let's Do] Meadow
minecolonies				MineColonies
minecraft					Minecraft (the game itself, I hope this is obvious)
mocreatures					Mo' Creatures: Nostalgia Edition
mowziesmobs					Mowzie's Mobs
outer_end					The Outer End
roll_delight				Roll Delight
rusticdelight				Rustic Delight
shroomtopia					Shroomtopia
simplyswords				Simply Swords
sleepy_hollows				Sleepy Hollows
some_assembly_required		Create: Some Assembly Required
spawn						Spawn
toughasnails				Tough As Nails
twikight_spark_delight		Twilight Spark's Delight
undergarden					The Undergarden
undergardendelight			Undergarden Delight
untamedwilds				Untamed Wilds
wildernature				[Let's Do] Wilder Nature

Thanks to my buddy Singing_Steel for bringing this to my attention, because I didn't think to test this for 1.20.1.