Can't get Tide Armor Trims? This could be the reason why!
The point of the video is that Vanilla Tweaks, a very popular datapack, texture, and overall minor Minecraft aditions page, has some conflicts with 1.20+ versions that is now fixed in its newest updates.
The video talks about the conflict with Tide amor trim, where the datapack "More Mob Heads" needs to be updated in order to not completely block the trim drop.
Hope this helps! ( Cause I killed 33 Elder Guardians in my survival world and didn't get a single drop due to this bug :] )