Your backsplash has enough color and texture to it that I would recommend a very quiet neutral color for your countertop.

Look for a solid countertop in one of the lighter colors of the travertine.

https://www.caesarstoneus.com/collections/supernatural/bianco-drift-6131/ this one could look nice but I would request a sample to make sure, because photos can do funny things to color.

I would get the countertop you want & replace the backsplash.

As a quartz owner, I wish I had known then what I know now. Something to consider if these types of things bother you.
https://www.npr.org/sections/health-shots/2019/11/21/777268528/it-s-going-to-get-worse-how-u-s-countertop-workers-started-getting-sick