At f/32 diffraction is so minor that its essentially meaningless in the print. In fact, it's right about that point you're actually starting to overcome film lack of flatness in a conventional 4x5 holder. In the case of the original question, there is no right or wrong. Use the challenge to actually study the ground glass image for ideal esthetic effect.
Learn to dance with the image instead of fighting with it. There's no way to tame it without resorting to a short focal length lens well stopped down for greater depth of field. Focus stacking is just a stunt. I've done quite a few cave and tunnel entrances, a similar problem. You simply have to prioritize what parts of the scene you need to be in acute focus and which can be a bit softer, and then judiciously use your view camera movements. Having a lens which is friendly to the rendition of those softer areas helps. But it's really an esthetic as much as a technical question.
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