Fully 3D printed guns are nonsense, at least of you are using an FDM or resin printer. Filaments and resins are just not tough enough to take the pressure and even when using tiny bullets combined with extremely short barrels to reduce the pressure (which will make the shot extremely weak) it’s a 50:50 chance on each shot to blow up the gun.

And if you have access to a €50k metal SLS printer, you likely have access to much cheaper tools for conventional gun building.

What is a thing though is combining conventional gun building (for the barrel and the other main components) with FDM/resin printing (for things like the handle grips) to remove the need for skills like woodworking.

And yes, the STLs for that are just a google search away.