What is the space to the right? It looks like a closet. If so, it's somewhat strange to have two separate closets reached only thru the bath. Do you need that much closet space? If not it will open up more design possibilities for the bath.

If you could close off that thin door, get shorter windows, you could put the tub down in that area, extend the vanity to a double, and enlarge the shower to where the tub is

really poor photoshop

if you don't want to move, I'd still move the vanity down a bit, (or, if you like the two vanities, get two 36" vanities and keep them where they are) If not, shorten the windows so you can have a longer vanity.

see if you can do something like these in that space where the tub is

Here is an idea that moves just the shower and a vanity.

I would try to do a pocket door on the toilet room, even if it meant moving the walkway and closet wall to the right a few inches.

You could hang towels near the shower and put a bench there under the window.

Given the twisting shapes of the bath and closets, it will be hard to create a functional layout leaving the walls and doors where they are. I would square off both the bath and the closet, providing access to the closet from the bedroom opposite the door. Leave the bath door and the toilet where they are, which will preserve the plumbing stack where it is. Build a full-width vanity with two sinks on the side wall adjacent to the toilet. Put a large glass shower where the closet currently is adjacent to the bath door. Then locate the free-standing tub opposite the shower, between the low windows. The tub will be the focal point as the first thing you see when entering the bath.

While you're at it, I would consider moving the bedroom door around the corner to open directly into the room instead of that awkward small "foyer" space. This would provide even more room for the walk-in closet.