You know what would be a nice callback but also completely out of left field for Superwomans identity?
Luma Lynai.
The "Superwoman" that Kal was in love with Pre-Crisis once but would die under a yellow sun like it was kryptonite to her.
She's not weak to Kryptonite, claims to not be a Kryptonian, wears a lead suit barring Daxamites, but worries about her containment field around her suit, maybe since the suit blocks out the yellow sun and gives her orange rays that make her strong?