Well, skarlet lost to Kabal and Sonya. Kit I'd a strong maybe as well. Cage? Lao?
Besides cyrax and kabal, all those are pure 5-5 mu at the worst, kenshi, sonya, Cage kitana, Lao, don't have any slight advantage on those mu.
She only loses to cyrax because he can still kill her with one combo at any moment, so she can't play some wild cards at will.
Kitana is a life lead mu, who ever gets to stay on the lead has more chances of winning, both character can turtle each other to victory.
Cage gets out zoned by skarlet, f3, ex nut punch is not a problem, daggers are.
Lao has problem hitting low hitbox characters skarlet is one, his good mobility evens the slight edge, she has over damage output and better hitting normals.
I'm sure you guys played some shitty skarlet, but do not forget she has the most broken armor, and can disable wakeups at nearly every single knockdown faster than anyone in the cast, which imo, put her with a top 3 oki game, and besides kabal, sonya, and cyrax, she can play those cards and be at advantage even when they guess correctly.