Disconnects don't necessarily have to be due to your local connection, though they can be. While the app could have an issue, it is also possible, and more likely, that other processes on your local network (other web usage, especially streaming) can cause disconnects, other processes on your device, or a problem between your ISP and the chess.com servers, which can't be controlled by the site or you.
I HAVE LOST NUMEROUS GAMES DUE TO AUTO RESIGN & DISCONNECT..WITHIN 1 MINUTE YOUR APP CLAIMS I LOST..I HAVE A VERY STRONG WIFI SYSTEM..AM SEEKIING OTHER CHESS APPS COZ YOURS SIMPLY IS RIDICULOUS...