wifi doesn't have valid ip configuration

My "Qwest Actiontec Q1000" modem has been, for a while now, only allowing some of the devices in my home to connect to it. Things like my Dell Inspirion 20 PC and only Apple phones have been connecting fine, but stuff like my Nintendo Switch, Samsung Galaxy A10E, Every laptop, and some old...

I want to get the Asus PG279Q (IPS Version) and I am wondering if a single 970 will be able to handle 1440p. What worries me the most about this card is the .5 Vram buffer, So my real question I guess is how easily/often is it for 1440p gaming to hit 3.5 Vram usage. Or should I just look at a...