apply attributes to already existing armour without modifying loot tables

is it possible to modify the data of iron armour to add armour toughness
im currently using a predicate to detect if a player is wearing armour, and if they are it runs a /item replace command. the issue is if the item is enchanted before it is equipped it will lose its enchants. idk how /item modify works but i couldnt find any info on it so im not sure if thats the solution