Conventional weapons can reduce hoards to manageable amount. And a zombie dragging itself across the ground is much easier to deal with.

If I saw thousands of zombies, a machine gun is what I want. Aim head at the average head height, and make the barrels smoke. It’s not suppressing fire, it’s crowd management.

Remember you can spike a zombie on the ground easier than when they are standing. Immobilise, THEN neutralise.

Artillery and bombs can shred/destroy the body, making it hard to move, if there is enough body left to move.

A .50 to the arm isn’t going to slow a zombie down, but the knee? Kinda hard to walk with one leg. 25mm chain gun is probably going to mist a few bodies.

Artillery is an area denial weapon. If you have a hoard a couple 105 shells are going to take apart rotten flesh with ease. Mortars are similar and more mobile.

Mine fields are effective as a way to immobilise and thin the herd.

Choke points work exceptionally well, and claymores can be rigged at head height.