https://bleedingcool.com/comics/lex-luthor-family-expands-superman-850-spoilers/
So Lex's mother is named Letitia in the comics but like Lillian on Supergirl,she's anti-alien(like Lex).
So this Lena is Lex's daughter.
Lena Luthor was originally introduced as Lex Luthor's younger sister, in the sixties, though this fact was hidden from her, when her parents went on the run.. In the New 52, she was revived as a paraplegic despite Lex's attempts to cure her. DC Rebirth saw her gain psychic powers, and creating powered clones of herself, before being locked up by Lexcorp.
But there is another Lena Luthor, the daughter of Lex and the immortal being Contessa Erica Del Portenza, who Lex keeps drugged and unconscious. Lena was aged to adolescence by Brainiac 13, and ends up playing both sides of that rivalry, before being regressed to infanthood. But she hasn't been around for a while. Looks like she's back…
Interesting note.The Lex on Superman & Lois also has a daughter who refused to speak to him when he was sent to prison by Lois eventually revealed to be false charges(the one thing he was innocent of). A big reason he wants revenge on Lois and Superman is because he blames them for destroying his relationship with his daughter.