Can you send a photo that shows where the backsplash is going?

I would go with square white tiles, actually, to look a little more intentional than a close-but-no-match size and shape and NEW looking tile. 4x4 or 6x6.

I can’t imagine subway tiles next to that.

Yep, select a larger scaled square for contrast.

Can you show a larger pic of the area to help us get more context? Is this wall above the countertop or in the same room and next to the backsplash?

I agree with others below that you may want a large square instead of a shape that too closely mimicks brick.