Given your situation I would try a light dose of veg nutes and some micros. That poor guy has been through a lot. If you can't correct it soon, you may want to start over. Your leaves almost have that twisted look of being nuked with N.Just my opinion though, good luck buddy.
My first thoughts were the same as MsSin's. Your canopy is pretty level. If you supercrop and bring your canopy out too wide, you will probably need support later in flower.
As far as increased thc, I don't know if it increases or not.
Not paying attention and picked a flowering plant straight up into my cool tube. Kinda smushed the main cola, by the time it finished it looked fox tailed with 5 heads to the bud.
Got lazy, didn't do routine cleaning of my humidifier, ended up with some bud mold.
I don't use LEDs either, maybe COBs soon. I based my opinion on what I've seen other growers with their LEDs to close. My first thing was a potassium deficiency, but with his ph at 6.1-6.2 potassium should not be locked out. .
If the off chance it continues to get worse after you raise the light. Start looking at root issues, that's unlikely as well though. I'm pretty sure it's your light. Good luck