Which ISP? Which modem/router do they use? It supplies the DNCP address?
Why did you get as 10 GbE adapter rather than 1GbE? Assuming you are connecting to the ISP router it is likely that it only supports 1 GbE via WiFi. My Comcast modem supports 6E but I still only get ~1400 Mbps, a bit more than wired ethernet's ~930 Mbps.
Can you return the OWC adapter? No experience with their 10GbE adapters but have had problems with some of their products.
WiFi problems are a b#$%#$% to diagnose.