Let us break them down into stackable shards. So you break water talismans down into water shards. Then at the altar we can fuse them to create water runes.
This gives us an almost stackable essence but it’s not overpowered because each can only be used at their respective altar, makes it easier to sink talismans from the game, makes it less of a pain when doing slayer as you can pick up and break down the talisman so it’s not eating more than one slot.
You shouldn’t get a ton of exp from this, both because you are combining shards to make a rune so I think logically the output should be lower and as it’s stackable you don’t want to break exp rates.
You wouldn’t even need to create new item models, use the unstable essence/rune model which already stacks. So you break the water talisman down into unstable water runes and then take them to an altar to stabilize them turning them into regular water runes.