The problem it shares with A Quiet Place
I just don't believe any biological life form can be so armoured that our small arms are reduced to - maybe we'll get lucky and kill it if we shoot it in the glowing red area, like some kind of video game monster.
Even alien lifeforms bringing perhaps weird and unique elements to the table with having some of their bodies covered in ultra hard armour. At the end of the day, it's just biological matter.
Just look at the type of ammunition we have available right now. Our top tier armour penetrating rounds. Stuff like M993, M995 etc. Most countries militaries have access to ammo that can shred steel armour plates from assault rifles, LMGs and HMGs. Not to mention big rounds like .50 BMG with all the specialty rounds available for that like APITs which would mess up most things I would argue.
Then we have the current trials to replace US infantry weapons in the NGSW program which will bump lethality up even more with even greater armour penetration capabilities at the squad level.
And then moving to the war in the future in the film. Almost 30 years of weapon development and they're still arming people with M4s. What is essentially an 84 year old weapon platform at that point. No directed energy weapons, no rail guns, not even caseless ammo. Basically zero innovation in small arms development in all that time. No wonder they're losing the war to a bunch aliens.
The only part of the film where you get a sense of just how we might be losing is when the aliens swarm the research place holding the queen. Now I'll admit, that is a lot aliens and it's no wonder that place was lost. Up until that point, you only ever see them in small packs which would be much less of a threat.