You could look at some floating floor options. Rolled are usually thinner and once patterned look quite nice. You may need to adhere a few spots if there is an exposed edge to traffic. There are a lot of cushioned material (if cockpit is used for family use), pvc or other harder materials (for rougher use) and some with holed patterns (facilitates draining). Look at garage floor products, work out floor products and outdoor sport court like products. I like these as they snap together and can be easily removed/updated if needed.
The biggest issues with the seadeck and like products I've heard are cost, durability and what happens when you need to remove. Most are glued down and the gelcoat will be impacted if you ever remove.
So many people are into "the look". With boats, you have to be concerned with "durability and reliability" over time. It is a harsh environment and gluing on top of gelcoat feels like a one and done to me. I wouldn't do it.