I am having a similar issue XPS 17 9720. Using a Dell 7-in-1 USB-C Multiport Adapter - DA310 to connect to Ethernet in office. The network drops up to 10 times a day. No other computers on Windows 11, or having the issue.   1. I connect to another computer hosting our QB's file, and when it drops, I have to go in and shut down all the other QB programs to relaunch QB.  2. I have turned off Wi-Fi, and disabled the adapter settings noted earlier in the post.  1. What a mess. That QuickBooks file sharing is already a bit rickety, and then it sounds like this is just peer-to-peer Windows Networking. A machine with a poor ethernet connection is the last thing you need. For sure, keep that QB-file backed up (made the proper way as a company-file.QBB ) 2. Good Try this: In Control-Panel / Programs and Featuresand/orSettings / Apps / Apps & FeaturesProperly uninstall anything related to:- Intel Killer Performance Suite (Performance Killer)- Killer Networking (Rivet, xTend, etc.) Killer of Networking- Dell Optimizer (Network de-Optimizer)- Express-Connect- SmartByte In Control Panel / Device=Manager- Delete the Wireless-WiFi deviceReboot computer.. On next start, Windows should auto-detect the WiFi mini-card and load appropriate (nice lean/basic/fast) drivers. Basically, run the simple Windows drivers (not that Killer nonsense).  Repeat process for Wired Ethernet device. Test operation.   
I have Dell XPS 13 7390 and Dell Thunderbolt Dock- WD19TB  but when I connect an ethernet cable to the dock or to the laptop it will disconnect from the internet for a few seconds and reconnect regularly.  WiFi works ok.  I have tried the ethernet with a different computer and it works fine. 
Ethernet wired connection keeps disconnecting