If I had a nickel anytime I saw someone ask why 2nd layer is broken because they do'nt have the 1.21.2+ pack, I would have waaaay more than 2 nickels 😂

Anyway, since not long ago (1.20.2 iirc) we can define pack overlay for different version of the game, wich is life savior to maintain a pack on may version. best part is that the pack still work in previous version without that feature :) It'll just be red for pre 1.20.1

{
    "pack": {
        "pack_format": 15,
        "supported_formats":[15,55],
		"description": "freshmoves"
	},
	
        "overlays": {
            "entries": [
			    {
                    "directory": "1.21.2+",
                    "formats": [48,55]
                }
            ]
        }
    }

Then you just add a directory 1.21.2+ in the root of the zip, in wich you put the assets folder and the files needed for this. the other versions will of course read the default assets
Not only people will not have to read some numbers, but you'll have to only manage 2 packs instead of 4 :p

Ps + might not be supported in folder names? :p