10x speed drop when removing quantum gateway and using Nest router

[NearlyThere]

Good day, 

I recently set up Verizon FiOS (internet only, no TV) along with Google Nest Wifi. In general everything works but I was looking to remove the Quantum Gateway (QG) directly. The reason I wanted to remove it is it seems to be a struggle getting to my home servers from the outside (I'll cover this in a different post if needed as my goal is currently to see if I really need the FiOS QG)

Description of setup:

1. I only have internet (gigabit), no TV
2. I already have a ethernet wiring from my verizon box to the QG (no coax to the QG)
3. Google Nest Wifi router is connected to my quantum gateway
4. QG is 192.168.1.1  and Nest is 192.168.86.1
5. QG Wifi is off, Nest Wifi is on. All my home devices are connected to Nest via WiFi 

Under this setup, everything works like a charm, doing a speed test directly on the nest wired router gives me a 800mbps download and 760mbps upload (approx) consistently

The problem:

I followed this sticky on how to completely avoid the QG and Nest gets an IP and everything else continues to work, however, doing a speed test drops the speed to 80mbps(d)/70mbps(u). This befuddles me - when Nest is connected to QG, it gets blazing fast speed. When Nest is connect to the eth cable from the verizon box, speeds drops. Why is this so? It can't be the cable or the nest router, because in the double router config above, it zips.

Thanks

[gs0b]

A speed drop like that is usually caused by Ethernet negotiating a 100Mbps link speed instead of a 1,000Mbps link speed.  To confirm, check the link status lights on the ONT or the router.  If they show a 100Mbps link, you've found the problem.

If it is a 100Mbps link, the very first thing to try is a different cable.  Even though it's working at 1,000Mbps with the Verizon router, it needs to be swapped out for complete testing.  Cables that aren't fully up to spec might work with one device but not another.  It will take you less time to swap cables than it took you to write your post.

Let us know what you find.