Right. In 2016 you can do most jobs with most weapons and you chose according to what ammo you have and your playstyle. In Eternal it's more that every enemy type has a weapon or two that are most effective against them plus the way the flamethrower and chainsaw work in that game.
Also just the contrast between 2016 being out-there with it's story and and "subtle" (in the biggest quotes imaginable) characterisation with Doom Guy always revolting against Hayden and others that give him orders compared to Eternal with its space fortress and sentinel lore and just a generally increased focus on story compared to 2016.
They are both great games but beyond the surface they are pretty different.