Replacing tiles in a non wet area is merely the sweat equity of demolition and disposal, plus the roughly $14 a sheet for new drywall, tape, and mudding. A under $100 project is the absolute lowest cost type of project that exists.

How about something like this:

This is a tuff one because painting the walls to match the tile would make them look doctor officy. Pale yellow would clash. Too bad sponge painting is a long gone fad---white and beige would tie everything together. My computer screen shows the walls as a pale icy blue and I kinda like it. if this were MY bathroom sweat equity would be a non starter because some of us just are not handy enough to replace dry wall or even tear it out.

P.S. when you paint the vanity blue--lose the old tired rug and buy a red one.

That is a very interesting combo of tile colors. Maybe try a greige-ish white color? Something like shoelace from Behr or similar?

As a temporary fix until a reno is in the budget get some glass etching compound. Carefully tape off those blue & red tiles. Apply etching carefully, clean thoroughly and let dry for a day or so just to make sure the grout around them dry as well. Get some bonding primer, and durable permanent enamel and paint them black (or other color). Ventilate and protect other surfaces and your hands.

Or, just disguise the red, since blue is easy to decorate around. the other option is to have all of the tile professionally enameled.

As for the walls, color match and lighten a shade or two will blend the tile color to be less contrasting. A sort of camoflage.