3 week old plants bottom leaves yellowing/browing/crisping

Make sure you are letting soil dry out completely between watering. Also increase the cal mag. I'm on phone so its cutting off names of your nutes, but I'm guessing that is gh calimagic @1ml/gal. Should be 1ml/L or 3.78 ~ 4 ml/gal. Would be helpful to get an EC reading, diary is saying .08EC, I doubt that based on what your feeding schedule is saying. Either way, I would hold off watering until they are dried right out. Then hit them with a light feeding thats heavy on cal mag. Good luck.

Burning from too much food, not deficiency. When starting with fresh, quality soil in decent sized pots, extra feeding should not be needed for the first 2-3-4 weeks after transplanting.

Think its toxicity, not lack. You in soil, make sure you have wet/dry cycle . Do not water while pots are still heavy, from overwatering you can get such look too, with mildly hot soil. Just take it easy, dont overpush. Good luck !