How does your computer's wifi work when you take it to another location? E.g. coffee shop. friend's house.
Update the firmware on the router. After the firmware update is complete, reset the router to factory defaults by pressing and holding the reset button for more than 5 seconds. Don't load your old settings. Just use the default settings for testing purposes. Typically on ASUS AC routers, the wireless mode should left on Auto.
https://www.asus.com/Networking/RTAC56U/HelpDesk_Download/
http://acer.custhelp.com/app/answers/detail/a_id/32747#_ga=1.114890823.1157921757.1473448280
https://support.microsoft.com/en-us/help/10741/windows-10-fix-network-connection-issues
You can start a new topic for the bonus issue.