You saying crunch time is destroying your sleep routine is where I push back. Sleep is NOT optional, it's fuel. I've seen people block out 6 hours for sleep no matter what and their work gets BETTER. Your brain needs that downtime to solve problems. Cutting sleep just makes you slower and more likely to mess up. Find one small change, like turning off screens an hour early, and guard that time like it's gold.
Man, I feel this in my bones from my last brutal project! What finally helped was forcing myself to take a real 20 minute power nap after lunch, not just more coffee. I also set one single, non-negotiable "hard stop" time each night, even if stuff wasn't perfect. You'll be shocked how sleep actually fixes the work.
You ever get so tired you start typing pure nonsense? I once tried to write an email during a bad crunch and my brain just gave up. The subject line was "Meeting about the uh the thing with the stuff". My coworker still brings it up. I'm the last person who should give sleep advice. I survive on bad coffee and the fear of missing deadlines.