What do you do? Well, I assume you have some sort of retention bonus or stock lockup that requires you to stay for a while if you want the money, so decide if it's worth it to you to stay, and quit if not.
If you decide to stay, you'll have to find a way to remove yourself emotionally from this work for a while. Stop caring about how long things take, and coast for a bit. Rearrange your time so you front-load things that you can do on your own, without onerous process or others' permission. Try to anticipate things you'll need to get done that will require coordination or help from other teams, and start that process as soon as you can.
I agree it's frustrating, and not what you're used to, but if the money is good enough such that you want to stick around for a bit, you'll have to adapt both your attitude and how you organize your work.