I have the newest quantum router from Verizon with 75 over 75 and the truth is the wifi range is NOT 325 feet away and it's located in front of a window, if i walk more then 25 feet away i loose wifi connection and thats on 2.4 and 5G and i also checked the admin specs from the browser(192.168.1.1) and everything was good there. Maybe the next router invention should include 2 wifi antenna's and also an SMA port for extended range of an out side antenna.
Becareful of windows.
Newer low E windows use metallic coatings/mixes. This can disrupt RF signals.
Try opening the window to see if you get a clear signal.
If so, it is the window causing the issue.