I have used Keel Eazy on various composite kayaks (and one ABS plastic) over a number of years and have been satisfied. The roughest use is landing on beaches - no white water with rocks, for example. I generally order from the Kayak Academy: https://www.kayakacademy.com/
A lot of the people in our Club were using KeelEasy but have largely given up on it. It works well for a couple of years and then the adhesive starts to fail. On a hot day the strip can shift off of the center line and it comes undone on the edges along curved sections. Where it comes loose the remaining adhesive picks up sand and gravel.
My boat is Canadian made and has a heavy layup along the keel. Almost all of the scratches seem to occur on either side of the keel, so KeelEasy didn’t really help. At this point I just touch up major scratches with a one step gel coat as necessary, usually every couple of years… Of course my boat is over 21 years old, well used, and consider it just that, not a fine piece of furniture. Exact color matching and minor cosmetic issues are not really an important consideration for me.