Waht ??? I have no clue about what the first sketch shows but for sure not the space you tells us about. The seconf sketch is the room you describld and honestly I have no idea the size of the vanity and am not going to count all the tiny squares to figure it out.. You will need space to walk to the toilet and that IMO min.30" I assume the vanity is only 1' deep. Wallpepr can give the illusin of a wider space if that wall paper is sometgind where it looks like you are looking out a window at agarden or mountains thst sorkt of idea.

Hi Larissa!
I think expanding the floor tile and pattern to the back toilet wall would definitely give the illusion of a wider bathroom (if possible, I would either: 1. reconsider the dark tile color to a lighter one, since dark colors tend to visually shrink a room, or 2. Use a light grout instead of trying to match charcoal tile, or 3. If you still want to experiment with the darker floor, consider using the same tile and pattern but in a lighter and contrasting tone on that back wall.
Additionally, place a floor to ceiling led mirror behind your floating vanity (this would probably have to be costume made but it shouldn’t be that much) I have attached photo for reference.
Lastly, don’t forget lighting!
I hope this helps…