lots of potential, if it were me,

I would address the floor tile grout first and recolor it so it is much lighter (tedious but will make a big impact) - add fresh pretty washable rugs from Ruggable to break up the white floor

I’d remove the tub slider doors and add a classic ticking (striped) *custom* shower curtain, hung high (above the ahower head) to make the most of the ceiling height (Etsy has great custom shower curtains) - make the width generous so it hangs nicely

remove the current med cabinet and light and find a nice sized mirror and simple, clean lined vanity light

I would replace the faucet with something larger, and more modern/angular

For hardware finishes (light, faucet faucet, cab hardware etc) , I might go black for contrast or chrome for something light/fresh

I would Paint the walls a classic khaki - fresh with the white and would be fine with the burgundy(?) striped tile

Eta - If you’re looking to replace the vanity - check to see if the tile floor runs beneath it and plan accordingly

I don’t love that tall cabinet in the corner - do you need all that storage? Can you get a cabinet that can be placed on the wall perpendicular to the toilet? Not sure there is enough room, but it could hold toilet paper, hand towels, a basket of small soaps, lotions, shampoos that your guests can use. If you do have frequent overnight guests, maybe switch to a larger shower head. You also need some art to give yourself a starting point for color. And if the vanity is in good shape, maybe a new top.

Can you put numbers to not breaking the bank and define minimal? Do you want to spent under $1k, $3k, $10k? Do you want to finish this in a weekend, hire a contractor? You show a picture of tile samples. Do you want to rip out floor tile, wall tile? Keep the glass doors?

On the lowest end budget, I had in my head exactly what La-la Girl wrote - khaki wall paint, new medicine cabinet and lighting. Spruce up the vanity or get a new one. I'd get another, more updated corner storage cabinet, one that is counter height. Hang art over it. Put the cleaning stuff and trash under the vanity.

Where are the marble tiles planned for ? IMO the lighting is horrible so is the pink wall. You need to be honest about the budget .. The floor grout needs major scrubbing and sealing that costs nothing . We need info posted here in comments OMG no khaki wall color ever in a bthroom

Add a great WALLPAPER that coordinates with the burgundy stripe. Replace the light fixture, and frame the mirror. Replace the vanity with something less downscale.

Unless you are gutting the bathroom, that marble-look porcelain does not belong with what you already have.

I love the wallpaper Minardi showed. Or paint the walls a light gray. I would like gray with that red stripe in the tile better than khaki. Our previous house had an old 1950's bathroom when we moved in that had gray and burgandy tile and it looked pretty good for an old bathroom. I did get a burgandy ticking stripe shower curtain that was in there until we remodeled, so I think it's interesting that la_la_girl suggested that. However, in your case, the white tile may not look good with a ticking stripe since sometimes they have a cream background which could look dirty against the white.

Without knowing your budget it is hard to make suggestions. What are you considering the marble look tile for? The floor, the vanity top? I agree with chispa, I don't see how it would work anywhere unless all the existing white tile is removed. I think you need to just paint, or do a complete remodel. If it were me I would spend as little as possible right now and do the complete remodel when you can.