I think, based entirely on what she said in Miss Americana, that she's kind of guided by her fears quite often. And she's always been scared that a day will come when the industry doesn't "let her" do music anymore, when she can no longer be successful. She's currently at the top top top of not just her game, but any artist's game. She's probably at least a little bit scared that this is as good as it gets and it's all downhill from here and wants to prolong her summit for as long as possible.
Or maybe she's just avoiding being stuck at home with Squirle Man.
Or, like the Gen Z intern in my office said, she's planning on taking time off to have babies. (I swear sometimes Gen Z seems way ahead of us Millennials and super liberal and other times I'd swear they're my grandmother reincarnated).