I had sandy dirt(well, still do under the semi-DL)...it was very, very stinky when wet,
both after a rain and even worse during spring snow melt.
Molds are everywhere and the changing environment of a deep litter could cause you problems if a mold bloom happened, it would normally even out if you had the right mix of ingredients, but you might not want to risk that. I don't 'see' mold, but that means nothing for your sensitivity.
I found early on that even tossing down a thin layer of straw can greatly help with the odors, but some mold could happen then too. No one can predict what would work for you in your environment.....a mask might be necessary when working in your run.