How do I cope when the standard work environment doesn't fit how my brain works?

You have done the hard part already. You learned how you work best and built strategies to get there. So when the standard environment still fights you, that is not a failure on your part. It is a room built for a different kind of mind, and you are making it work anyway. Some of that friction you can shape, and some you have to spend energy managing. Learn to tell the two apart. The open office you might fix with headphones or a quiet corner. The meeting that drains you might need a heads-up to your manager instead. Aim your energy at what actually moves. Pick the one part of your day that costs you the most, and ask for a single specific change this week. Not a whole overhaul, just one thing. You are not asking to be accommodated out of weakness. You are removing a needless obstacle so your real strengths can show.