The REAL default gender is there isn’t one. Same as race. There isn’t one. The default of these things is a question as to what the thing is.
Like, I should have been saying, “I’m thinking about a lich – what gender is it?”

Course there could be exceptions for things that are, in fact, typically a specific gender. Like a priest or a nun or an impidimp.

Anyway sorry this is a little late, I am sick again! Yay! (this is because I have children and children have NO HYGEINE WHATSOEVER.)

Side note, most the art of Lolth I can find depict her as a drider. And 5e lore is pretty clear that driders are the results of displeasing/failing Lolth – a curse that other drow despise. So like, it’s weird to me that Lolth would consider her own image a curse, and that making her followers to be remade in her image to be a punishment. That’s. Weird. So that’s why I didn’t make her a drider.

Maybe the lore behind driders was different in earlier versions (I did have to check because I thought it was a blessing so maybe I was remembering something older instead of just getting it wrong?), I could check, but it’s irrelevant at this point.