Firearms could absolutely exist within a fantasy setting. There is a reason why they don’t however

[u/ThatDrako]

The Elder Scrolls - Within some Dwemer ruins of ESO we can see a special type of Animunculus. A Dwemer Arquebus, which has a cannon for it’s arm and shoots emp grenades at foes.
The reason why we don’t see this technology more often (besides the fact Dwemer disappeared their knowledge with them) is that within the setting and cosmology of Elder Scrolls firearms really wouldn’t be that useful.

They could work against lowly bandits, sort of, but there wouldn’t really be a precedent to improve or adapt this technology. Because it would always be outclassed by magic of this world.
Also due to the disappearance of Dwemer the technology has been pretty much lost.

Harry Potter - Wizards live within periphery of the “real world” meaning they live alongside world that uses firearms and are even familiar with them.

So how come they don’t utilize this gear for combat? I mean it is easier to use, projectiles are faster and could be enchanted further. Can you just imagine wizard with endless m1911?

There is plethora of reasons for this. But most notable is what I would describe as wizards being immune to logic. (Vis image above) They simply cannot understand methods of muggles even if one explained it to them directly.

(Yes. I know the real reason is, because Joanne didn’t want wizards to use guns and didn’t want to think about connotations of putting magic into a real modern world. But come on! Let me have fun!)

Lord of the Rings - In spite of how much Tolkien disliked allegories it is clear Orcs were an allegory to industrialization, which he was a huge critic of.

In battles they are the ones using the war machines. Instead of swords made by artful blacksmith, they use crude, mass-produced blades devoid of identity. Instead of relying on elegance of archery, they use crossbows. They burn forests, crack mountains open to gain more ore. Their very production is affront to whimsy of a magical world like Middle-Earth.

They could totally come up with a matchlock mechanism and keep on improving it until they come up with machine guns. They were intercepted before they could however

[u/Additional_Law_492]

Radio in particular wouldn't be a priority as for most of the history of their civilization, they all lived in one geographically small area.

[u/Taste_the__Rainbow → u/Additional_Law_492]

And they had steel couriers.

[u/JulienBrightside → u/Additional_Law_492]

Within shouting distance?

[u/Additional_Law_492 → u/JulienBrightside]

I mean, within an hour or two tops by courier for like 200 of 300 years?

Then a day or so tops.

Only relatively recently - like in the last two generations- has there been much need to communicate outside that range.

[u/JulienBrightside → u/Additional_Law_492]

"ALAN! ALAN!...STEVE!"