The real marble makes the quartz look fake...

Could you use same countertop for backsplash? Not sure if okay around stove would need to check. But not a fan of the one you have it’s too much, so maybe go with a color, a soft grey or a white.

Try a solid backsplash. Get a good color by looking at counter and tile together in varying light conditions.

I don’t like the combo - too busy & looks like tried to match patterns but missed.. I agree with comments on getting solid BS - let the countertop be the star. The pattern that the tiles will create is enough interest for BS. Tonal shades of one color for BS - grey to match counter veining could look good. Just make sure the white / cream whatever of counter is same in BS so you need to see actual pieces in your space & lighting.

Never mix natural stone with manmade. The differences become quite obvious.

Too much.

Thought so thanks everyone!