Bro your PH is too high : 7ph in coco isn't recommended, you should try to stick to 5.8 to 6.3 with a sweet spot at 5.8 so it is the 1st reason why your plant could/will remain short and have deficiencies. I see in the comment that you found a solution against spider mites : I would recommend neem oil to keep it organic. Concerning the temps I would try to settle a difference between day and night temps just to imitate the natural environment parameters. Last observation : your feeding chart looks weird , try to find the flora series coco chart on Google and tweak it a bit if you want And don't forget that coco requires more nutrients than a soil grow ππ