XPS 9310, WD19TB, poor ethernet connection speeds

I am having the same problem. XPS 9710, with Windows 11.

When I install the December 2021 Windows 11 - 1153.3.20.1102 - driver directly from RealTek - https://www.realtek.com/en/component/zoo/category/network-interface-controllers-10-100-1000m-gigabit-ethernet-usb-3-0-software - I get full GB speeds.... but it restarts the network connection randomly sometimes a few seconds, sometimes a few minutes.

If I install the November 2021 Windows 10  - 10.48.914.2021 - driver on the WD19TB support page - https://www.dell.com/support/home/en-us/product-support/product/dell-wd19tb-dock/drivers - it stays  connected, but maxes out around 100Mb.

I don't have the option to use another model of dock. The proprietary way Dell exceeds 100W PD charging means I'm stuck with it. 

Good afternoon, 

In office we have 15 Dell XPS 13 9310 connected to Dell Docking stations WD19TBS which via "LAN"
for the last 3-4 days (at least for my laptop, today checked rest colleagues confirming they have it too), have an issue with random packet loss / time outs 24/7, even when office is closed. As a result there is a drop in speed test as you mention and some random disconnections in various programs e.g web radio, vpn connections etc.users started to complain. Speedtests range from 5mbps to 220mbps but very unstable. 

In local lan ping from laptop to the modem , time outs do occur to 15-20% of the packets sent, and as a result can see general failure message as well. Note: without being accompanied by increased latency. In reverse ping from the router to all lan devices everything is ok, except the laptops themselves that show packet loss. After further troubleshooting (yes EVERYTHING was tested) the problem was found in the specific model docking station we have WD19TBS (its sister model of yours).  With a differnet Dell series model that we tested, we face no problem, speedtest goes 400mbps stable, no packet loss and all other parameters are the same). We also tested speedtest/ping via WiFi had no issue at all.

Tested usb LAN driver 1-2 versions back, without luck. Checked NIC parameters (green energy jumbo frames etc. to be disabled, problem remains. Contacted Dell that told me to arrange replacement directly... "without troubleshootin?" i asked , and they replied its their policy for docking stations... ! 

I have sent them an email and asked for their colleagues to look into my issue and contact me for feedbaack/troubleshooting/test any test firmware etc. 

Will further look into it next days until replacement is arranged, cause to replace 15 docking stations will take some time and personally don't like that approach, anyway will revert.