Leave it alone unless you are an experienced tile professional or can afford to hire one. That is far harder to FIY than you think. Especially the demolition and not damaging the things you want to keep.

For the tub, I’d probably do a stone deck and paneled sides. Check out a stone yard or two and see if they have the same granite that’s on your countertop.

For the flooring, a neutral, SIMPLE, stone-look porcelain tile would work well. Just make sure they’re bigger than the ones you have now so it looks more current. ;)

Btw, I actually like the current color on your walls and cabinet. What color are you planning to change them to?

Pick a solid tile which matches one of the lighter colors in the sink counter, or better yet, a “stone” porcelain tile with a non-slip slightly rough surface.

DIY for tile depends on your comfort level with learning a new skill and having the right tools. A wet saw and properly toothed trowels and the most important.

I was thinking of balboa mist on the walls and rode iron on the cabinet and frame of mirror & window frame for the colors.. I was also thinking of putting beboard around the tub and then just paint the tile around the tub! Then maybe do a floating floor?

That tub looks dangerous. Tiling will be a lot easier & less expensive with the tub gone.

What color is your vanity, mirror frame and toilet now? They look nice. It just looks like once you get that floor and tub together you will have a very nice looking bathroom.

Have you considered peel-n-stick for your tub surround?