Should ask the user to review the app after 1-3 launches.
Consider adapting ReviewHelper class: https://gist.github.com/colinkiama/e56bb527191dfc89a9bb00ffb76e3f8b

Whenever the user holds a key down, the fade timer still doesn't reset itself, meaning that the user could exploit this and not write any actual content

If a key (that adds characters to the text box) is held down for a brief period of time the fade timer should no longer reset itself when more characters are added.

User should have the option to reach a certain word count instead to finish a session (instead of writing until the session ends)

While there is already the (Windows + Shift + Enter) UWP Full-screen mode shortcut, there should be a user-friendly way to access this mode in the app too.