Can I still have a Career - Overworked and Going on Maternity Leave

I'm sure this is a common theme and people have great feedback for me. I have been working my ass off the last five years as I changed my career to tech and was able to move my way up to a Product Management position, which was my goal and I love it! I feel amazing that I am finally where I want to be in my career, but a multitude of changes happened this past year. My company was sold to a much larger company that doesn't have the same amazing culture as my previous one, my developers were laid-off and replaced with a team that is in an extremely hard time zone to work with. This compounded as it's hard to find daycare during odd working hours, and my husband is busy running his own business, and now I will have a second child. I love my direct team that I work with, and have an amazing manager who is flexible and truly interested in my personal growth but I am not a fan of the company; we are severely understaffed, and the migration has been extremely difficult as everybody has left and no one knows the applications anymore or how anything works. And with the second child coming, I do not think I can work this crazy schedule anymore and support seven different applications. I am trying not to let my scarcity mindset control the narrative in my life, but I am feeling a bit burnt out after two years of this environment and need to take a break from work and focus on my family. Continuing to work in this environment will only cause me and my family to suffer. Of course, I worry as most women do... will it be difficult for me to get back in the workforce in a couple of years? Are there things I can do besides taking online courses to keep myself fresh and relevant? I don't want to let my already understaffed team down but what's the best timing for quitting? Before or after maternity leave? Should I let my boss know I am quitting waaaaay in advance, or will this screw me over personally? Thank you for taking the time to read my story and help a woman out <3