I would point out here that the idea that Lois can’t both be “free” and be married to the man she has loved for 80 years is a strain of the exact sexism we are talking about though.
This is a cultural issue and one women have been fighting a long time. Women like Lois should not have to be alone in order to be independent and free. There are absolutely some women who would prefer to remain uncoupled and go through life on their own. But Lois has fairly consistently for 80 years expressed fairly clearly that she wants to be with Clark/Superman.
Women don’t have to be alone to be free. We can be free and still have the support and love of a partner. We don’t ask strong men to go it alone to prove their strength and independence and we shouldn’t ask strong women to do that either. Being alone is a perfectly valid life choice for many people and it’s a choice many people make for a variety of reasons. But it’s not a choice that Lois Lane has really ever consistently expressed wanting so I’m not sure I get the reasoning for trying to push characterization on her that, frankly, is inconsistent with who she is.
As to your other point about Clark finding someone else to marry....why? Why is this the one aspect or the story that has to shake up? Lois is one of the founding elements of the story. She was around before he could fly and he’s loved her for that long. I don’t see people regularly arguing that Clark Kent shouldn’t be from Krypton or have different parents. I don’t see people arguing that he shouldn’t fly or have heat vision. Yet, she pre dates all that stuff. Yet, she gets treated as a variable despite being one of the only constant elements in the story. Essentially seen as replaceable by another random love interest in her own story. It’s bothersome.