summon minecraft:armor_stand ~ ~ ~ {Tags:[shulker_holder],Invisible:1b,Marker:1b,Small:1b}
$item replace entity @n[tag=shulker_holder] armor.head from entity @s $(container).$(slot)
summon minecraft:item ~ ~ ~ {Tags:[dropshulker,itemguard],Item:{id:"minecraft:stick",count:1},PickupDelay:40s,Invulnerable:1b,Glowing:1b}
data modify entity @n[tag=dropshulker] Item set from entity @n[tag=shulker_holder] equipment.head

$item replace entity @s $(container).$(slot) with air
kill @n[tag=shulker_holder]
tag @e[tag=dropshulker] remove dropshulker