Kormiya

if you want to get an item's count, the new snapshot content will be confused, beacuse you cant directly get the count of an item by /data get entity @s Item.count
to get the count of an item which wont go wrong will need to be
/execute store result score @s 1 run data get entity @s SelectedItem.count
/execute if score @s 1 matches 0 run scoreboard players set @s 1 1
beacuse you cant know that is an item with 1 count in components, so it will be fail, you need to manaly set it to 1, also decreased efficiency

to check an item with count is 1, by using this

/execute if data entity @s SelectedItem{id:"minecraft:bedrock"} unless data entity @s SelectedItem.count

as the update, an item without count components will be 1 by default.
so you can know thats an item with one count