Your bathroom isn't... typical – very small or narrow and it's a problem.
It's not easy to place anything in it, not easy to find a good place for shelves etc.
Look... there's few examples for good small, square, rectangular long, or narrow bathrooom planing.
With us, all weaknesses of your batroom become adventages.

With ceramic tiles it is easy to make a shelf under the washbasin. Mark the zone around the washbasin with a different colour of tiles, borders or decors.

Put the washing machine in a wall recess in the bathroom, mount some shelves above it, and cover the whole with blinds.

Mix the colours to make your bathroom more joyful.
A built-in compartment will hold small items.
Fiesta