How to store execution result on entity arbitrarily without effecting gameplay?

I need to store the amount of one item a player has in their inventory to their own entity, but I need to store it in an arbitrary way that doesn’t effect the gameplay.
If this makes it any clearer, I want to simply store it on the entity to be accessed later, I don’t want to store it to "Score" or something that will change anything in the gameplay.

I know this much:

/execute as @a store result entity @s ***PATH*** int 1 run clear @s minecraft:netherite_ingot 0

I don’t know what to put in the path to be able to access the data later.

I tried storing it in the entities tags, but I couldn’t find any way of accessing specifically the first tag. I searched for an answer, and tried things like Tags[1], {Tags.[1]} and {Tags.1}

Does anybody know how to store data to an entity in a different, arbitrary way, or how to access specifically the first, second or third tag of an entity?