I continued with the nutrient plan and started adding again BioBloom, TopMax, and for the first time also Alg-a-Mic and Acti-Vera.
I also always have to do further LST to keep her down.
At Day 53 latest, she outed herself as a girl.
@Zarayju, Sorry for the late answer, I was not checking here frequently.
I've bought those from Lientec-LED. They also offer a lot of DIY-Sets. Keep in mind to also order some aluminum profiles, as the heat of the LEDs needs to be dissipated.