Thank you everyone for your input! I especially appreciate the photos, it is helpful to see examples. I think I will have it end where the upper cabinet ends. But I'm still trying to figure out an edging solution. One end of the tile is glazed so I may consider using the glazed end on the edge as Lake Girl suggested. I did see a photo of someone on this forum that did that (could be Lake Girl but I can't remember). Otherwise I may use the Schluter edging if it blends w/my tile well enough. They are sending me samples of their three gray colors and their brushed nickel. (my tile is gray)

I'm not seeing a current picture witht he sink -- just the one with the paper down on the wood which I understand to be before use. That wall looks like it has a raw end of drywall, not a side that is finished (paper or whatever) or maybe even no drywall. It looks like they tried to smooth joint compound in there, either by itself over your studs and built up or over something less than a full side of finished drywall. Joint compound will turn to mud (that's what they call it when it's wet -- hence the verb to "mud" the walls) and dissolve away if it gets wet. Paint will only seal the surface, and if water gets behind it -- well, I dare say it is probably worse than damp sheetrock, which is worse than damp green board. You say they had to sheer away your window sill. Did that sill come below the window too? I don't think you've got clean drywall there. I think you've got a really poor job of mudding and an even worse job of sealing the joint. That's my guess.

I have had nothing but problems with my CAULKED grout at the base of my backsplash, where it meets the quartz countertop. It repeatedly cracks. I have had the contractor come back in and redo this area multiple times. I will no longer allow the tile company he brought in to do the job because they were so awful. Despite their brag of being in the business for years, their grout guy used regular grout at the backsplash base. Then they sent in another guy to cut it out and replace it with caulk. Despite this, it continually cracks. Every time the base cracks my contractor tells me this is movement in our 30 yr old home. My prior backsplash and counter, which was ALL tile ALL grout never had this issue. I have to pay the contractor to fix the seam every few months. Can anyone tell me why this is happening and how to remedy it? It’s really bad. The cracks are the biggest I have seen yet.

You'll find it both ways. I don't think one is right or wrong, just personal preference. Ours from PO goes to the edge of the peninsula. I hate it. Wish it ended with the wall cabinet. Without uppers it looks fine going to the edge of the peninsula