How to fix Sea of Thieves not opening to Fullscreen Exclusive / True Fullscreen / only being Fullscreen borderless

This 100% worked when using PC / Xbox Gaming app

1. Open Xbox app
2. Highlight Sea of Thieves
3. Click the three dots near the play button and go to manage
4. Click files then browse
5. Open Sea of Thieves folder
6. Open content folder
7. Right click SeaofThieves.exe then properties
8. Under the Compatibility tab check Disable fullscreen optimizations and then apply. You can close those open folders now
9. Launch the game and start a game load fully into an adventure, legend, or tutorial
10. Your mouse should now stay on the screen where the game is, until you hit the windows key