As a story writer/author, this is my opinion:
This movie was not bad. I really liked the aesthetic of all the Barbie stuff, the plot kept you hooked, and the acting was done well. I also enjoyed the feminist aspects of the plot.
The problems, though, were the excessive sarcastic jokes about mental health, all referring to depression, anxiety, and "thoughts of death". I was especially bothered about how they stereotyped depression: the script said something similar to: "Depressed Barbie just lays in her bed and scrolls on Instagram all day!". This is not a great portrayal of depression since it's educating people inaccurately about it and they are only encouraging its stereotypical traits.
Plus, the plot essentially just jumped from one thing to the next. The beginning was when Barbie was in Barbieland, then later she came to the real world, then she randomly decided to come back to Barbieland (while accompanied by "real world" humans) after these men working for Mattel tried to put her back into the Barbie box. And all the Kens kept going from battling, dancing, and dance-battling, which was overdone and also made the plot pretty confusing.