Mostly routers don’t handle 10 devices at once, at least the ones I am aware of, mostly. If they are sleeping, they might occasionally ping your system, but they shouldn’t cause much of a slow down in service. I think the exception here is the iPhones, which do continue to run programs, even when they appear to be asleep. We have an iPhone, 2 computers, and 2 tablets here. Right now, the iPhone, a tablet, and both computers are on, and one tablet is sleeping. We have good service, but this is a pretty good modem/router (300). You can go bigger, or smaller, and that will change your service.