Sometimes when you just get connected to a new provider it takes a few days to settle in. Could you do a speed test close to the router (with your phone maybe?)

Unplug it from the wall, wait five minutes and plug it back in. It’s going to be fine ;)

That’s weird. Maybe clear CMOS ?

That’s not a lot of information to go off off. The computer works fine outside of gaming? Try reinstalling the drivers ?

You’re probably fine if you change all your passwords. Don’t click on anymore dodgy links ;) And McAfee is not great but not dangerous. If anything weird happens reinstall windows.