I can only offer some additional troubleshooting steps.
Your network connection is fairly simple so I would suggest you take NM (NetworkManager) out of the equation and setup your network device manually to see if that eliminates your issue. This goes back to the comment (@despotic_machine) and log listing the p2p and wireless interfaces. Seems like the NM may be trying to setup your wifi interfaces. Though looking at the log you provided, it seems NM sees the wireless interface, identifies that it is not connected, and sets it to inactive. So, there may not be an issue. I had issues with NM many years ago on a laptop and preferred wicd; however, it seems that development has stalled on wicd. Regardless, I do not run NetworkManager at all on my desktop (just isc-dhcp-client and entry in /etc/networks/interfaces) since it is not roaming (plugged into a switch). It seems you don’t even need to uninstall anything, just setup the network manually and NM should leave the interface alone. If you want it to be clean, make sure NM is not running, or purge it from the system and setup your networking manually. The assumption of manual setup is based on the debian wiki:
If you want to stick with NM, it seems you can change the logging level to see if you get more details. I would check the man page or documentation for NM for instructions for debugging. I would expect that you can disable interfaces in NM to reduce the likelihood of some fringe case that is plaguing your setup. Since I don’t run NM, I can’t provide any detailed suggestions.
More of a question but is the switch or router also the same device for the last 2 years? Is it possible that the network device is misbehaving and causing the desktop to lock up? This would feed into @0v0 request to wireshark/tcpdump from a laptop or other device connected to the router/switch to see what’s going on traffic wise.
I can only offer some additional troubleshooting steps.
https://wiki.debian.org/NetworkManager#Wired_Networks_are_Unmanaged
NOTE: Unless you know networking, this is probably going to take you down a networking rabbit hole, so glhf.
Some Debian references regarding networking and different configurations:
https://www.debian.org/doc/manuals/debian-reference/ch05.en.html
https://www.debian.org/doc/manuals/debian-handbook/sect.network-config
If you want to stick with NM, it seems you can change the logging level to see if you get more details. I would check the man page or documentation for NM for instructions for debugging. I would expect that you can disable interfaces in NM to reduce the likelihood of some fringe case that is plaguing your setup. Since I don’t run NM, I can’t provide any detailed suggestions.
More of a question but is the switch or router also the same device for the last 2 years? Is it possible that the network device is misbehaving and causing the desktop to lock up? This would feed into @0v0 request to wireshark/tcpdump from a laptop or other device connected to the router/switch to see what’s going on traffic wise.