It’s probably a matter of preference in the end, but I actually found it much more intuitive to decouple the pillars from the walls in the final modules. That allowed for a 1.2x scaled wall section to make these angled sections; in real game design, it would also allow you to randomly rotate the pillars around for more damage variation, and to replace some of them with a new variety if you make more later. Not strictly better, since you largely have to place pillars and walls separately, just a different approach.
And, that said, @Grant_Abbitt 's instruction on joining meshes made my wonky dungeon chest much easier to create, so yay! ^v^