I think I realized how I handled mapping wrong during last session.
The first mistake was giving Tim graph paper instead of blank printer paper. The second was giving him dimensions of the rooms. These combined let him generate a more-or-less canonically accurate map with high precision.
For some reason, I get the impression that this isn't how things are supposed to work. Like PC maps are supposed to be sketchy and iffy, with creating one being an act of artistic interpretation and reading one being an act of intuition and not a little trepidation. To this end, I think ditching graph paper for players is probably a good first step. I also think that having a rule of "DM is not permitted to look at player map" would likely help, but that's slightly more extreme.