Hey, I grew Durban Poison photo some 1.5 years ago. I remember problems at the beginning, 2 failed and 3rd seed success. It looked similar to yours at that stage but I got through it with foliar feed, Urtica nettle brew. Mine was smaller scale grow but not much stretch after the switch (if compared to ie. Kalichakra, Mandala Seed's sativa). In 5L coco always 45 grams dry, 1 from seed and 2 clones. I have no early stage pictures but this shows the stretch best (at 20 days in bloom):
https://www.autoflower.org/media/dp20.16798/full