I got Mxy a bit mixed up with Music Meister for a moment, but as you say, the timing’s basically the same and if next episode ends up with them officially together as the last Mxy ep did, that’s still far too close to S2 for my tastes. I mean, the whole William thing comes too close to Mon-El for my tastes already anyway - he was a jerk to her, then he wasn’t, they get closer once the audience has had time to decide he’s a good guy, he pushes for something more, she says she doesn’t really feel that way about him when secretly she does but she’s got some other hang-up about it, people in her circle encourage her to go for it anyway, Mxy shows up and messes with her, she goes all in, etc. I didn’t need to see this bad attempt at a romance twice. It didn’t work the first time, and every move in it feels incredibly forced and transparent by the writers.
And yes, Lois & Clark dragged out the reveal for 2 seasons. But it was Lois who revealed she knew (and was mad about it), because Clark the Dummy decided to propose to her before telling her, lol.
I’m not opposed to Kara dating someone while trying to keep the secret (maybe not for two whole seasons, but for a little bit at least), but William just ain’t the guy, imo. He brings nothing to the table, and their “romance” has already been botched enough for me to the point that I doubt these writers could do anything to get me to root for them.