The statement about JYP being traumatized by Suzy's success is not accurate for me. That company not traumatized to whatever happens with Miss A. It's obvious when Jyp tried pushing Tzuyu to emulate Suzy's success early in Twice's career, but the flag incident caused them to shift strategies and focus on promoting Twice as a cohesive group instead—probably originally at first, only until the controversy died down. However, it slowly became part of their identity instead of just a temporary PR move, as people love Twice as a team. Twice became a well-loved group known for their chemistry, relatable image, and strong teamwork. It works really well, and Twice has a huge stable fanbase with huge sales since their rookie era more than Jyp's gg before them thanks to this too aside from their good choreography.
Overall, Jyp's strategy with Twice has proven successful, as they have a strong fandom and continue to sell well after 7 years, unlike Jyp past girl groups. Jyp was also able to renegotiate contracts with the entire group, benefiting the company.
For Itzy and Nmixx, JYP seems to stick with the group-focused strategy that worked for Twice. Why fix something that isn't broken, right? It worked for Twice, and it will likely work for Itzy and Nmixx too. It will make things easier for the company too, to just focus on the group mostly instead of handling each members' schedule. However, Jyp may have overlooked the importance of media relevancy in this generation of K-pop. Which is why it's not smart for them Jyp to fully make these two groups following Twice step in term of this. And also, the gg competition today are really fierce where before compared to 3rd gen landscape.