Target block NBT

[snakercz_]

Skript Version (do not put latest): Skript 2.5.3
Skript Author: Bensku
Minecraft Version: 1.16.5
Addons: skDragon, Skellett, SkQuery, skRayFall, skUtilities, SharpSK

So basically, I have this problem. I want to check if target block of player is specific head, and if it is, change it to different head. I have solved how to place the specific head, but I can't get it to recognize the NBT data of target block. It just works on any placed player head. Any help would be appreciated!

on chat:
    if player's tool is blaze rod:
        if message is "Watela" or "Watela!":
            if {xyz.spell.Watela.learntime.%player%} is more than 5:
                if target block is {xyz.spell.Watela.item}: # <--- this is what does not work. the variable is set to specific head. but it works on any playerhead item.
                    send "&7&oSomething happened with the item..."
                    set {_x} to rounded down x-coords of target block
                    set {_y} to rounded down y-coords of target block
                    set {_z} to rounded down z-coords of target block
                    set target block to air
                    execute console command "setblock %{_x}% %{_y}% %{_z}% minecraft:player_head[rotation=0]{SkullOwner:{Id:""bdb8ba17-0fbf-433c-88d8-6dbd4129ae3c"",Properties:{textures:[{Value:""eyJ0ZXh0dXJlcyI6eyJTS0lOIjp7InVybCI6Imh0dHA6Ly90ZXh0dXJlcy5taW5lY3JhZnQubmV0L3RleHR1cmUvYTRiOTNmNDE1MzJmYzI3ZWY3ZGY5MzNjMTgxYWMzMTY2ZDU2MDM3ZDVjNWZmNzVkMmU4NWFmZTM3Y2EyNTdkMyJ9fX0=""}]}}} replace"
            if {xyz.spell.Watela.learntime.%player%} is 3:
                send "&7&oNothing really happened... try again." to player
            add 1 to {xyz.spell.Watela.learntime.%player%}