What is the best way to finish the gap behind our kitchen sink?
When our kitchen sink was installed, the contractor used a thick bead of GE clear waterproof silicone between the sink and the countertop, including along the back where the sink meets the wall/back panel. It didn’t look very good because the silicone was quite thick.
When we removed the silicone, it pulled off the paint behind it as well. We ended up filling in the damaged area with different shades of nail polish to try to match the surrounding color. For now, my husband puts a towel behind the sink to keep water from getting into the gap, but it looks terrible and we’d really like to find a better permanent solution.
There is approximately a 1 cm (about 3/8 inch) gap between the back edge of the sink and the wall/back panel. I’m not sure what this area is technically called or what the proper way to finish it would be.
We tried filling the gap with GE Advanced Silicone 100% Clear, but even though it was labeled clear, it dried cloudy rather than clear, so it didn’t look good.
There is already silicone underneath the sink from the original installation, but there is currently nothing sealing the exposed edge/gap along the back of the sink.
We don’t want to keep using a towel, and we also don’t want to have to constantly wipe water from this area. We’re concerned that repeated wiping could eventually damage the nail polish we used to touch up the paint.

What would be the proper way to finish or seal this approximately 1 cm gap so that it looks neat, or put there, to keep water from getting behind the sink, and doesn’t require a towel or constant wiping? We’d especially like a solution that looks clean and unobtrusive rather than another thick bead of silicone.

Any suggestions for the right product or method would be greatly appreciated! Please see photos.