Are potions and ingredients discarded when crafting spells?
This looks like someones custom game they are planning to release at some point and reading the rules it's not clear.   If you know they people making this game there are quite a few things in the rules that are not totally clear and could be worded better.  I think I understood what they meant based on playing games but this set of rules would benefit from pictorial examples of actions being taken.
The rules say

Use ingredients to craft potions. Discard the two matching ingredients
listed on the potion

and later

Use a combination of potions and/or ingredients to craft spells.

Based on other unclear things in the rules I think that the fact both those actions have the word &quot;Use&quot; in them suggests. you are meant to discard card for spells.
Another reason to think this is because potion cards are arranged in stacks of 4 and that each player may only have one of each type.   If this was a 2 player game and potions were not discarded when making a spell there there would be no need for a stack of 4 as only 2 of each type could ever be taken.
Also in end game scoring there are points for 'unused potions'. If they are not discarded how would a player know that is not used.
This is however a best guess as the rules could be improved.