Bread – follow recipes for bread-machine breads without bread machine

It may be because of the type of yeast being used. Quick-cooking bread machines (1 hour cycle) typically requires "instant" yeast which rises much faster. Standard-cooking bread machines (2-3 hour cycle) need regular yeast, which is active longer. It sounds like you're using instant yeast in a standard recipe; thus the yeast stops working before the bread machine gets to the second rise cycle. Under-cooking may be because the resultant dough is denser than the machine expects, thus doesn't heat through in time.

Unfortunately the trade names for "Regular Active Dry" yeast and "Instant Dry" yeast can be very confusing.

I agree that cornbread will not have the structure you need since it's close to a sponge cake. Instead of modifying a cornbread recipe, I would recommend modifying a pie crust recipe.

A standard pie crust is approximately 3 parts flour : 2 parts fat : 1 part water. To achieve the cornbread flavors, replace some of the flour with the cornmeal, as it can serve the same purpose as flour in this case. You can also replace some or all of the water with milk or buttermilk. If you do not like the grainy texture of the cornmeal, soak the cornmeal in the liquid you choose for several hours to overnight.