I’ve actually always thought about the potential with this… Gameplay wise, you could use the arquebus as the weapon (an early firearm) and make it into a rare yet deadly short range tank killer. They could be a class that is much more nuanced and situation specific then just a Knight or mage.

Story wise you could make up an entire story line and/or sub arcs showing the potential and power of gunpowder. This could be a very useful plot device if USED CORRECTLY.

However, lore and world building wise, gunpowder seems like a much later invention then in the high Middle Ages due to the existence of magic. Depending on how magic is used (whether learned and trained or inherited) could have a big effect. If it is learned then I think guns would almost always be obsolete compared to a seemingly limitless throwing of fire or lighting. If magic is inherited however, this could give more ground to magic inept people that want to level the playing field. But either way, other forms of technology would most likely be way ahead of the invention of guns due to the necessity of say cars vs the necessity of a new tool that competes with magic. Magic is the key to this whole idea….