I know how to type Capital letters in Apple Watch Password
1) Scribble the letter you want to be a capital.
2) Tap that letter (a dot) until it gets a ring around it. You’ll see your letter, rather than a dot.
3) Rotate the crown until the capital version of your letter has the arrow pointed at it.
4) Wait until the ring disappears, and the cursor moves to let you scribble the next letter.
5) Count you characters (dots), because scribble EASILY adds SPACES that appear as dots!
Apple Watch Series 5, watchOS 8