I would just leave them. As accent strips go, they are not offensive.

You can’t touch them without causing damage to the waterproofing underneath so leave them alone.

I did it. I used a utility knife in the grout joint...then pried the tiles off. Damaged the drywall...then touched it up with hot mud. The new accent strip has been in for 27 years....yeah....it's working out just fine. (it used to be 2 tiles wide of aqua blue colored tile)

Caitlin....the hard part was finding a border I liked that fit in the space. :0) It's sooooooooooooo worth it!

It's risky and time consuming. If you do this, first remove the grout between the strip and adjacent tiles. That lowers the chance of damage.

But--if you do damage any of the adjacent tiles, do you have a fall-back option? Spares? If not, you are screwed. So screwed.