@moxii 

Switch Deco mesh to Access Point mode and there will be no settings in it that could impact wired link speed: Switching a Deco to Access Point (AP) Mode

Also, just to cover everything, check what does Rogers Ignite router reports for port speed connection from Deco X55. If it is same model as mine, this is the screen you should check:

Hi thanks for the quick reply.  I was playing with the router and found the issue.  I forgot I activated the QoS back when I had a lower ISP package and limited the Total Bandwidth to 1000Gbps.  When I turned off QoS, I was able to hit 1.7Gbps.

Question though, why is the QoS Total Bandwidth limit maxed out at 1000Mbps?  It doesn't allow me to enter any number higher than 1000Mbps.

Yes, I have 3.7.11 installed on my iPhone.  See attached screenshot.

  @moxii Out of interest, are you on firmware version 1.3.0 on your X55 Pro/s? I am certain several bugs were introduced with 1.3.0 relating to QoS, your issue being one of them (see here for someone with the same issue as you but on X50 Pros which are functionality the same device as the X55 Pro, even sharing identical firmware binaries: https://community.tp-link.com/en/home/forum/topic/661248). Unfortunately I don't have any 2.5Gbe capable hardware yet so can't confirm I see the same issue as you had but the 'some_person' user in the thread above has.

I have the X50 Pro too and when I updated from 1.2.5 -> 1.3.0 , my internet dropped immediately. This was caused with the update from 1.2.5 -> 1.3.0 as it happened instantaneously upon updating and QoS worked fine on the previous version. I can also reproduce this issue 100% of the time as enabling QoS in the app drops my connection instantly (regardless of the values set) and disabling it makes it work again instantly. I've logged a fault with TP Link support about this, but haven't heard any update as of yet.

  @moxii 

This definitely smells like some kind of weird QoS issue with the update. I reported a similar issue a while back (though apparently after yours, and on X50 Pros) and these were ultimately my findings:
 

• Link - Findings

TLDR - my line speeds were being capped at 1G after updating to this firmware, even though I had QoS enabled for the device for 2500 Mpbs. Blowing the configuration away after firmware update seemed to fix it.

And to share, I did attempt a repro (to follow up with a TP Link support thread) and my findings were this:

• Re-enabling QoS (with a 2500 Mbps bandwith limit) and re-adding my wired laptop (connected via USB-C-to Ethernet adapter rated for 2.5), speeds were still capped at ~1G.
• Removing the device from QoS configs resolves the speed cap issue, again.