Can I please get some help??

3 white widow, ff ocean forest/coco mix, 3x 300watt led, couple days past 3 weeks into flowering.
One plant has these brown spots on it, and they are rapidly spreading. They started out in one area and seem to be spreading to every leaf that's close or touching. The other 2 plants have a spot here or there. All 3 plants stems have turns purple-bright red wherever they are exposed to light. All three plans, the leafs are clawing, and curving. Almost every "cola" that isnt a main branch is becoming a lighter green every single day, and on most, the tips and some edges are slightly purple. The lower growth that is getting no light, or little light is yellowing and dying off quite rapidly. The buds seem fine, but seem to have slowed growth dramatically. The plants have grown vigorously up until about 2 weeks ago. Right around the time I gave them there first feeding ever, flower feed of course.
I've researched and researched and I cant find anything. A ton of stuff that's "similar" but not even a single picture that looks the exact same!!
I've put a ton of work and time into this and I would seriously hate for it to be for nothing..
If the spots are a fungus of some sort, all I have is neem oil that I could try to treat it with. Just transferred jobs so I'm very tight on money right now and can't really afford much.
I would really appreciate it if someone could please help me.
(Sorry about the purple lighting, I have no other light for taking pictures)

FFOF runs light on my cal/mag, IMO. You need to give them some veg nutes in flower, especially if the flower nutes are really low on N. Kind of a myth that thei nutrient needs change that dramatically in flower, still need some of everything. Good luck, look pretty nice overall!

Thanks for the reply!
I gave them some N and flower nutes the watering before last, and gave them more N and epsom salts for Mag this watering. I'm hoping things turn around.
After reading more, I think they may be having a phosphorus deficiency. The curled down growth/red stems, the stiff dryish feeling leafs are all symptoms. And also symptoms of cal/mag deficiency.
Brown spots are aswell, but the way their spreading I'm worried that it's fungus):. I've examined a ton for pests and nothing. The underside of the leaf where the brown spots are has sort of a ring shape..
I can deal with deficiencies easily, but I've never dealt with fungus or mold before, and I'm not sure how to

They're loading up on trichomes, I just haven't noticed any crazy bud development. But maybe they still haven't fully passed through the stretch phase, and need some more feeding. The day after Christmas I'll definitely be giving them a good feeding

Bro you have slight N toxicity imo, dial down the veg nutes, and the microscopic picture looks like a salt burn to me, a necrotic spot, overfeeding does that. Too much N also locks out other stuff like potassium.

I've literally fed them n twice throughout the entire grown and both at 1/4th strength... but yeah its N toxicity.... lol

Not trying to come off as rude, but I said that in my post. I mean maybe somehow it is.
But like I said throughout the entire grow I've given them almost no nitrogen, and very little nutrients all together

First of all, i think phosphorus deficiency is possible so does cal and mag, seeing they are flowering. But i also see downward looking tips, veiny and dry looking older growth and your ffof is rich in nitrogen. All these makes me think about nitrogen toxicity. Of course under blurples not much can be said about the colour.
Don’t really need you to take my advice on anything, simply ignore it if you don’t like. No need to reply to it at all.

The feedings seem to have just started to clear up some of the symptoms, but the brown spots are spreading like crazy... not so much over a huge area, but every day they affect like 3 more leafs, and by the next day they are COVERED in brown spots..
Any help??????