Until we were able to remodel our horrid bathroom, I hung a shower curtain on a tension rod on the outside of the shower stall glass. With your busy tile, maybe do the same with a solid shower curtain and a matching curtain at the window, white or ivory or the lighter color from the tiles. Coordinating towels.

Can you use 3M hooks on the walls? If you remove them properly, they don't leave mark.

@bpathome I like the idea about the curtains for the window! but we arent even allowed to use hooks so I don't think we could do it on the shower.

But you could, with a pressure-mounted rod! The hooks go on the rod, Or, how about suction-cup hooks? Or, square-ish hooks that hook over the top of the frame?

@bpathome Yes! I realised I can get hooks that go over the top of the frame and that would totally work. thankyou!! :)

Luxurious thick towels and a big thick washable bath mat. Choose a color you love. You could also add a wonderful Speakman shower head that you will take with you when you leave.

Hard to know what the actual colors are because monitors read so differently, but on mine the tile looks yellow and gray, so I'd probably do plain fluffy towels in those colors (or whatever the real colors are) and a plain or textured gray shower curtain (as per bpat) and the window. You can use a tension rod for the window. The biggest bath rug you can manage, to cover most of the floor, so only the wall tile shows for the most part. Then I'd put a second rug/bath mat and hang it lengthwise on the side of the tub to cover some more of the tile.

White also looks luxurious unless the finishes are at all dreary/worn, then white sometimes makes everything look dingy. But try them all and see what works.