What kind of deficiency is this or is it light bur...

So you got a few things happening here , Your day time and night time temperatures are to close I would say minimum 6 degree difference is needed , you can fix this buy adjusting your exhaust fan to run higher or have your intake fans blow cooler air in . Second thing I'm noticing here is HUGE deficiency CalMg is a must !! This is causing the yellowing on the leafs . You are also having a Potassium and Phosphorus deficiency biiiiiiiiggggg time this is causing the dark spots as well as aiding the yellowing of the leaf . If this isn't corrected you will eventually have leafs that turn yellow yellow yellow not from nutrient burn but from lack of nutrients ! I don't think you have a heat issue because although some of the leafs that are really damaged are curling they will do that when they are dry dry . The rest of the plant show's no signs of heat stress there's no "taco-ing" on any of the leafs except the ones that are already damaged beyond repair . If you fix these things and trim away all those dead leafs your plant will heal and continue to prosper ! The reason I say get rid of the leaves is because they are a perfect home for unwanted pests ! So its best to avoid that all together ! I hope this information was useful and helps you on your journey to become a grow master ! -Happy Growing!

Burnt edges check. Uneven yellowing on the top half of the leaves, check. Rust spots, check. Affected leaves are the older (lower) ones, check. That's classic K (potassium) deficiency. Also, dark, metallic blue patches, check. Severly affected leaves curl, wither and drop, check. This other one is classic P (phosphorous) deficiency. You are in serious need of a bloom nutrient, try getting a PK booster. Had it been calcium, the affected leaves would be the newer ones, since it's an inmobile element.

I think its a bit troublesome that your night temp is only 1 degree less than your daytime temp, they really need to go down 5-10 degrees less at night otherwise i may think its a heat related stress. In the last photo i can really see the "curled/cupped" leaves which usually shows a heat/light stress. Im no expert by any means, but maybe try placing the light a few inches higher, keep the roots cool (kelp helps with this stress), and cool your night temps down. Also check the manufacturers recommendations for light heights. I hope this helps slightly. Keep up the fight ✌️