Smart Switch lighting neutral question

I own a commercial storage unit where I keep my boat, trailers, etc. I went to install a Smart Switch in it, so I could remotely control the lights if needed (i.e. some times I will forget to turn them off when I leave). I bought a witch, took the cover off, and realized I don't have a neutral (or so, I think). But it is not as simple as just having the neutral up at the light. Running a neutral would not be feasible as it is about a 70 ft run through a mix of EMT, flexible, and inside the wall. So I bought a switch that doesn't need a neutral, but that didn't work because the unit has non dimmable LED lights.

Anyway, I am trying to get my bearings about how this is wired and cannot figure out what it looks like up in the box at the ceiling (23 ft high and not easily accessible). It is a 2 gang wall box, with a light switch and a variable speed fan switch. They share a common 20 amp breaker and a single hot. That is about as far as I can figure out. I have attached a diagram. If anyone can shed some light on how this is all wired up, I would greatly appreciate it.