Not much bcz most of it going towards the kitchen...

Get a colorful, fun shower curtain, and then get a rug and some towels that pull colors from it, and a much lighter shade for the walls.

Shower Curtain Unique from DiaNoche Designs by Carrie Schmitt - Wild Divinity · More Info

Bath Rug Cotton and Microfiber Hand Loom, 50"x30", Arctic Blue, Pattern Bubbles · More Info

Flossy 3-Piece Turkish Cotton Towel Set, Green · More Info

That and a faucet should be good for a long time, after which you can get going on a larger plan.

Acm's ideas are great. Add a couple of shelves above the toilet to expand storage. Or some art.

Assuming your assuming your vanity is a standard size, a replacement top with sink from a big box store would make a huge improvement along with a framed mirror and new cabinet door hardware. I once had a small bathroom and was able to find a reasonably priced quartz top for it and it really improved the look of the bathroom.

Awesome ideas ty