Paid maternity leave? 9% put into your 401K up front, then a 3% match on whatever you put in? GIRL PLEASE. Stay and hit your 3 year vestment.
You sound like an overachiever, and it's hard for overachievers to hit a good job and relax in it. After 30 years of pushing yourself through school, college, internships and climbing the career ranks--feeling like you're not challenged can feel like you're in a dead end job and stagnating.
I'm going to flip it around and show you that your boring job is actually the best place to stay to focus on starting a family:
1. Bored now? GREAT! Being pregnant makes most women sick and exhausted. You want a job that you can do with your eyes closed because, sometimes? You'll be sitting at your desk with your eyes closed trying not to be sick. (Imagine trying to impress a new boss when you're dizzy, nauseous, and just want to go lay down anywhere...even the floor right here...because you're so miserable. Or, trying to work through a 90 day probationary period like that.)
2. "But I'm already slacking and coming in late..." No company wants to go through the legal hassle of firing a pregnant coworker. As long as you're putting 70% effort in and getting your job done, you aren't going to be fired. Most coworkers/bosses are going to be understanding and not expect 100% from you anyway (although not all--occassionally you run across some hardcore drones who think everyone should live 100% for work). <---ETA, I'm also willing to bet that YOU think you are slacking but literally no one else in your company thinks that about you.
3. PAID MATERNITY LEAVE. This is so ridiculously rare in America. I'm jealous.
4. While you're on maternity leave, you aren't going to be worried that Slimy Steve is vying for your position. You don't actually *care* about your position, so you're not all that worried about it. If you lose it, you'll be happy to go out and find something better! You can relax and recover and 100% focus on your family! (Also, by law, your company has to hold a position open for you *at or above* the level you left at. Maybe, just maybe, you'll come back to a delightful lateral move!)
5. When you come back to work, you're going to want a job you can do with your eyes closed. You're going to be exhausted and way more interested in what's going on at home with the baby than what's going on at work.
You have the rest of your working career to find a more exciting job. If you're planning to start a family, this boring established job is the absolutely BEST job you could have for it!