There's this enchantment called "Alchemist Blessing" that can supposedly "transmute items" but I don't know how. All I know is that it needs a beacon
I'm using the latest 1.12.2 version

You need an anvil, Shift-rightclick it with your Tool with Alchemist Blessing, it will then transfer Redstone into the Tool.
Then you need a beacon, throw the items to transmute on the beacon, and rightclick the Beacon.
A list of what can be transmuted can be found here.
If the item is not on the list, it will turn into EXP. If you have no more Redstone in your Tool, it will consume durability

Do you right click it with the item enchanted

Yes

I tried that, but it didn't work

is your beacon actived? Do you get the benefits of that beacon?

oh I never gave it any effects, next time i'll try that and see if it works

It works

Ok closing.