Putting enchantments on wrong equipment for bonuses until item/armour breaks

I know a way.

Instead of actually using soul speed enchant levels, you could make the tunic give speed to player while they are standing on soul soil or soul sand. I can explain further if needed.

Alright I'll try to explain it better

You could create a procedure, in this example, I'll call it soul_speed_booster.

In the procedure editor, set the external trigger to be, "on player tick".

Then add an "if" block, and for it's condition, use an "=" block that can fit item data, then grab an empty data block of the same color from the "minecraft components" tab and double click it to set it to your item.

Grab a block that can sense what is in a certain slot of the player or entity's inventory, and put it in the first slot in the "=" block, and put the data block that shows the picture of your item in the second slot.

Then, in the "if" block, put in an "if else if" block. In the conditions for each, put an "=" block that can fit block data.

In the "=" blocks' first slots, put the block you want to detect, e.g. soul sand, soul soil.

In the second slot, add a block to detect the in-game block at certain coordinates, make those coordinates be x, y-1, z.

Then, inside the bodies of both empty "if" blocks, add the "add effect" block, with the effect you would like to apply, e.g. speed, and make the effect ambient and not show particles, set the duration to 1 and the strength to whatever you like.