Yes. Siliconized latex from the same manufacturer as the grout.

I'd tape both sides of the joint and use an unsanded color-matched grout or clear grout - really squish it into the joint - smooth it, and remove the tape. There is also a runny crack sealant for these spots. I don't remember the name of it, but my tile guys used it in a couple of spots.

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.

Any change in plane is to be caulk not grout. Grout will not move with the walls expansion/movement, it will crack. TCNA standards are caulk,