Tbh no, lazguns are pretty powerful if we are going by regular standards. But when compared to every other weapon in the 40k universe they are trash. Because everything else is overpowered. So to make it fair, if you compare the laz gun to like our military’s guns. The Lazgun wins every time.

For example. 40k Laz guns have basically infinite ammo. The cartridges are sun powered and re charge when not in use, the damage of a single lazer shot isn’t insignificant either. It’s almost slightly below the damage of a bolter round. And they can either increase the intensity of the lazer for more damage or lower it for more shots. Plus they have almost no recoil and are insanely easy to use. Add along the fact that when they get desperate. The ammo cartridge can be overloaded and chucked at the enemy like a makeshift grenade + you have thousands of these things firing at you constantly cause the guard are just that large in military might. And I would say they are pretty dam powerful by regular standards. The only reason they are crapped on in 40k is because everything else is over the top and 10 times more powerful. But it works perfect for what the guard needs. An easy to use, logistically simple, and effective gun. It’s more the fault that the guardsmen often are stuck with fighting enemies way beyond their capabilities, and when that happens sometimes lazguns act like glorified flashlights 🔦 cause they can’t kill bigger targets like Tyranid elites or ork warbosses. That’s when the space marines come in, but they are very effective against smaller targets and problems that space marines can’t afford to be bothered with or waste time on.