I going to trash about 400k in equity to leave and that's acceptable to me (nothing is vested), but with hiring and salaries being crazy right now, is it insane to take a 6mo-1yr career break? I have savings, but I've only been making 150k for the last few years and I'm worried the opportunity cost here is too high to ignore.
If you just don't want to stay at that company, maybe find a new job first, before quitting? 400k in equity is a pretty decent amount. Also, although hiring and salaries are crazy right now, so are the interview processes.
You might not even need a career break. It sounds like a notable company that's a good resume item. Why not just move on to another company? There are plenty of well paid tech companies that value their staff. The good one will usually have very long interview processes though, as a lot of them will look for trust (i.e. you're not toxic) so it might be better to search while employed.
Life is too short to imprison yourself.