If you are set on one or the other I'd go with the more plain as the other will be dated much faster if not already.

For a flip, I'd use the first, but I sort of like the second for a little subtle interest. I hope you can remove the 4" backsplash of stone, though, before you start, since you really only need one or the other, and the combination looks like an awkward retrofit.

Agree with above, but didn't want to offer the other options available that would have more longevity as you seem to love this?? Carolyn is correct.........it's a tiny bit dated what you have.

2x8 glass subway Home Depot

Your granite is already busy so you don't want your backsplash to be fighting with it. Go for the first one, but like everyone else said a glass subway tile would look better. Also, remove that granite border since it will be unnecessary and won't look good with the new backsplash.

You already have a granite backsplash so IMO you either just leave it or remove that 4” piece and then do tile

Yes, if you're changing your splash, the existing 4" splash must go.