I believe Carla is the second worst champion and probably the luckiest fighter in UFC WMMA history. No one has won more with so little skill, deserving so little.
She won the inaugural SW belt against an opponent with very little experience. When she had to face an experienced fighter in her first title defense, she got demolished.
She wasn't really on a 5-win streak when she got her second title shot. She got gifted the decision in at least 2 of those fights. Xiaonan, who has no grappling at all, was the only opponent she beat convincingly. Then she got gifted the belt doing nothing in a "fight" that should have been a draw, only to get destroyed again in her first title defense.
In an interview before Namajunas vs Esparza 2, Tatiana, who's a much better wrestler than Esparza, said Carla has good technique but isn't strong and predicted she wouldn't be able to hold Rose down. Joanna said the same thing. They were right. Carla couldn't hold Rose down for a single second. The one time she got her back, Rose shook her off like she was a kid. And Rose took her down with absolute ease in the fifth. Rose could have probably even outgrappled her if she had tried to fight.
Funny thing is that the most inactive Rose ever would have won the "fight" throwing 2 more punches per round. That's literally all it would have taken to beat the person that according to Kyojiro has her number. The reality is Carla's that doesn't have the number of any of best fighters in the division. She doesn't have the skills, the size nor the strength to pose a threat to any of them. She needed Rose to boycot herself and do nothing to get gifted the belt in what should have been a draw. She most certainly beat the champion to become the champion.