If you’re not in a position to have it changed now you could try some inexpensive press on tiles to camouflage the tiles you hate. Pick a color that blends (not trying to match) the wall tiles. This might be enough to get you to the point of finding a replacement tile and hiring an installer.

Live with it until such time you can swing re-tiling it all again.

looks fine. put some nice bottles in the niche. when you're ready to retile, get what you like

you don't paint glass tile. it's not porous and not meant for wet areas. it's going to peel and look worse than it does.

Leave it allone and please no peeland stick tile ever in a shower. They could be a lot worse maybe for now just go with the flow and add some nice towels in the same color family add anoter nice color that works for stuff on the counter and add a couple of towels in that color in the stack.

Congrats on your new home! Live in your home 4-6 months and you will start noting other things that drive you crazy - prioritize, budget, and plan to save to pay for what it takes to make this a wonderful place to live. In the meantime add colorful bath towels to take your mind off the accent tiles.

What @marylut said. ^^^