> "I wanted to let you know that I'll be staying remote from here on out. This last year has been a huge improvement in quality of life for me, and honestly I couldn't imagine working out of an office again. I'd love to stay with you guys (this is a great team), so let me know if that's an option. If not, I'm sure I can wind down my projects by next month."

I'd leave out the last sentence, it doesn't add anything and just makes the threat to quit more in your face thus confrontational.

Also instead of finishing with "so let me know if that's an option." I'd go more like "so let me know what options we can explore to make this happen." The first one is a take it or leave it, the second says you're flexible on details as long as you get to be remote.

The point is that you communicate that you are very interested in staying, love the team and willing to work with management to find any reasonable solution to make this work. If you make it an ultimatum the more likely response is "Sad to see you go, ok bye."