So here is my situation and question

I'm redoing my bathroom. Was taken down to the studs.

It's been drywalled. 70 inch vanity installed and shower enclosure and floor tiled. I have decided to shiplap the wall wall where the vanity was installed. No counter top has been installed yet. Should I install the shiplap before I put the counter top and backsplash or should I set the shiplap on the top of the back splash going up?

I'm assuming the best way to do this would have been to install the shiplap before the vanity was installed.

Please advise. Thank you.