Streams like a dream over 4G but FIOS is consistently terrible like 100% of the time.
I'm the only one using the internet here and it's still terrible.
Also why is my connection insecure ALL THE TIME? Some sites block me, saying my connection is insecure.
Who's the man in the middle of my connection?
Insecure connections are either caused by browser settings or firewall settings or even antivirus or anti malware programs.
I would look at those options first.
additionally I would check with a friend to see if he can bring his laptop or tablet to your place and try to go to the same websites. If his device gets service then you know it’s your devices on your network.
next would be a defective router or a bad network setup. In this situation you place another router in to test it. Then unplug the computers, tablets etc. and then place them back on after the replacement or test router is fully booted up.
if you can now get to the sites you could not go to before then it was a bad router setting or bad router.