can't tell if this is heat stress, russett mites, or fungal infection

My plants were fine, symptomless essentially up until yesterday. Had a minor magnesium deficiency because I use a shit ton of gypsum. Also I'm in the mojave so my humidity is less than ten percent but I water ateast every other day and they're in 20 gallon pots. Also the temps are a usually betwwen 75-85, although after this i dropped it to 64-70. I've used a microscope and I can't find any mites or eggs.


Also the day before this happened I sprayed a neem, Botaniguard, and magnesium sulfate spray to combat a clue gnats I saw buzzing around and correct the magnesium deficiency I saw. I hit it once, bit hard. Which I didn't think would be a big deal. I've hit them with agsil multiple times, and once Zn, cu and humic acid and they burned but survived.

And another reason I don't think this is fungal is I add a shit ton of zn, cu b, mo, mn to my soil. Also I water in kombucha a lot, but haven't in a while. My soil is young but I have worms in it etc. I just bought biota maxx that has like 4 species of reich in it just in case. I'm really debating cutting down most of them to save the ones that are good. The one plant has black splotches in the leaf as well.

Just looked under the microscope again at the blacker splotches. Pretty sure I see filament and this is fungal. Two plants have been culled and I added a shit ton more zn, cu, mn, mo, b, to my soil. Idk if I'll be able to save my crop though. Fuck