Input delay, 4K resolution issues, pages loading slowly or incomplete

I have been dealing with a network wide input delay that I cannot diagnose and would love some assistance!

My current setup includes: EPON connected to XB8 Modem/Router(orange lined port4) in bridge mode, connected to Asus RT86-U wan port. (1G Down, 1GUp.) 

All devices connect to Asus for wifi and wired access. 

Nothing is hardwired to the Lan ports of Asus, only the Asus Router itself is connected to lan port of XB8. 

CAT 8 SFTP cables are uses for all wired connections. 

The same Asus router was previously used with my bridge mode setup with former ISP, and no input delay was on the network.

No settings on the Asus router have been changed. Old setup was with COAX, current is with Fiber. 

QOS settings are disabled. 

This is a new install at my house. Our neighborhood has only had Xfinity for about 4 months. When the initial install took place, a temporary line was installed, and the tech installed a XB7-T combo. At that time, I did not have any input delay or issues on my devices at home. About a week later they finally installed the temporary line into the ground, and that is when I believe my issues started. After a month or so of frustration, I have since attempted to replace the XB7 with the XB8 seeing minor improvements. I have reset and restarted the Epon, XB8, and Asus more times than I can count, with no solution found. I have removed the Asus router completely from the network and still have the input lag.

I have yet to get a tech out, because I don't want the trip fee if they deem it my equipment, so I am attempting every troubleshooting avenue that I can think of. 

The interesting thing to me, is for the most part, speed seems unaffected. Speed tests show appropriate speeds, but latency is around 110ms for both download and upload speeds using Ookla, via a wired Windows computer. This remains true even if I remove the bridged Asus router completely, and use the XB8 in normal routing mode.

If I remove the XB8 completely, and wire directly from Epon to Asus router, input delay is gone, but I don't get a wan ip issued (XB7 or 8 is required with EPON service). 

Considering I can't use the service without the use of the XB7 or 8 before my own router, this leads me into thinking that this is that it is related to the line that they installed in the yard. 

Any suggestions would be greatly appreciated.