You can adjust settings, and I do, but once you clear an area if you stay near the area the options are either "randomly spawn in zombies where you've cleared" (ignoring whether a zombie could actually path there or not, last I tested it) or "no more zombies". There's no built in way I know of to simulate a glob coming in from the edges of your safe zone if the edges are farther out than the limit of cells it simulates around you.

I could probably get something together with the horde night mod. Just haven't had time to tinker lately.

I'm sure there's a combination out there that would get what I'm looking for. I just haven't found it yet, and a lot of the scene (especially what gets coverage by youtubers) seem to be focused on increasing difficulty by making individual zombies more threatening (night sprinters, randomizers, adding different "zany" zombie types) or adding environmental hazards (nuclear fallout, airborne virus, eternal winter).

That's a sub trope that makes me wonder: why animate a corpse when animating the skeleton alone achieves the same purposes? For visual impact?

And even in magic universes, physics still afects everything. Frost freezes the undead, heat cinzes their flesh, etc.