first try to exclude software driver issue by doing a clean install of Windows.

If issue persists and you suspect the integrated gigabit hardware is defective

try Dell oem add in ethernet card for 7070 tower

I'm looking at trying to use the 2nd M.2 slot, just for something different, and to keep the PCI slots open. 

Something like this: Amazon.com: IO CREST 2.5 Gigabit Ethernet Mini PCI-E Network Controller Card 10/100/1000/25000 Mbps RJ45 LAN Adapter Converter for Desktop PC,SI-MPE24073 : Everything Else

But you can see there are several versions. Would need to make sure getting one that is compatible. 

But today I found one of the network cables bunched around and up under a power strip. Maybe freeing that up will eliminate some static or whatever. Have my fingers crossed. 

There are few things more annoying than a random network disconnect. 

No matter what you are doing, even in the middle of a zoom call for an important meeting, boom, you have to reboot. 

I did a clean install of windows and that did make the problem much better, thought it was solved actually, but it returned. 

Re: Something like this: 

the amazon card is mini PCIe and not M.2

you meant something like this https://www.amazon.com/LIANXUE-Ethernet-Multi-Gigabit-Networks-Industrial/dp/B0CL5XQ6ST

@redxps630​ 

The link I posted has several different versions, it looks like a few of those are similar to what you found.

But I've also run the DISM repair image function, and then SFC scan:

DISM.exe /Online /Cleanup-image /Restorehealth
sfc /scannow

It found a few files to fix, not sure if they were directly related to the network card.