Your problem was most definitely the Big Bloom nutes during the veg stage. Theres nothing wrong with MG as your soil, you just have to know how to work with it. MGMC soil already has nutes in it so during the first 3 weeks to a month only give it Ph'd water (which I did not do...I fed her and gave her a slight burn) after that you can give it a diluted, say 1/4 strength feeding, and gradually increase the dosage. I have never given my baby a 100% strength feeding but thats just because I'm being (over)cautious. You live, you learn, just chalk it up to experience.
Heres a link to my current MG grow if you wanna check it out.
https://www.rollitup.org/marijuana-plant-problems/193796-about-ph-2.html