Question on GUI specific item textures (JAVA EDITION)

I looked at all the threads for this and realized they were very old so, I'm gonna ask this again, is there any ways with texture packs to have one texture of the item for the GUI only, not in your hand (GUI = basically your inventory).



So for example I am holding, an iron ingot, but in my inventory it shows as a gold ingot.



IMPORTANT: I actually found a way to do this but it's really complex so I am checking if there are simpler ways.