Is my onboard nic defective?

[MrAlfredBuddyGuy]

I have a Minisforum UM480XT at my office with Windows 11.

 

I often have connectivity issues. RDP is timing out/reconnecting. Or trying to access network shares hosted by this PC  sometimes is just unavailable briefly.
I'm connected over ethernet and wifi is disabled. I've never had RDP issues with other pcs on my network.
Is there something specific I can watch for in Event Viewer to see what might be going wrong? Or maybe some other utility I can use to see what might be happening.

The problem is very intermittent. Sometimes the connection issues are back to back within minutes making it feel unusable, and other times it seems to go quite a while without any problem.
Incidentally, as I'm writing this, I've been RDP'd into this system for quite some time and haven't noticed anything. Also, I'm connected to another RDP session that I use every day on my PC and I don't see this same warning while I'm getting it on the problematic pc.  Reminder, this is all within my local LAN, no outside access.