Cold Water pressure problem

I have a bit of a mystery and challenge with our kitchen sink, and the problem only exists at that one location. The cold water pressure is reduced around 80%. The faucet is fairly new and we tried replacing the cold water valve under the sink. When that did not work, checked the water pressure in the cold water pipe source and it is low even before it gets to the sink.

Ever have a problem like this? I talked to one plumber who suggested there could be something called a "checkball" that came from the hot water heater. A small part broke free and traveled through part of the pipe and is stuck at a joint where the 3/4" goes to the 1/2" connected to the sink. The solution is to cut drywall in the basement and search for that location.

I hate the idea of cutting drywall in a search that is not even guaranteed with success. I am not finding much doing my own research. Anyone else experience something similar?