Devuan (Debian without systemd), stable (Daedalus) with backports. Been running Debian since 2000, Devuan since 2018. I am at a point where I just want consistency and familiarity in my setup.

Edit: as far as cool new things, I have moved to pipewire for audio and leveraging a selfhosted nextcloud for web based file storage. For a personal setup (limited users) I just installed Nextcloud office which is basically Libreoffice in a browser like Google docs. I am also using mythtv with an hdhomerun for broadcast tv. None of this is really "new" but new to me. The setup of these functions has been fairly straightforward for me and I appreciate all the work these projects have put to make the setup and maintenance fairly painless.

I can only offer some additional troubleshooting steps.

1. 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:

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

1. 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.

2. 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.

Thanks for the appreciation post and I agree, 4.18 is very good. I started using Linux around 1997/1998 (RedHat 5.0, Dec 1997)...so, I am also old... While I played around with different window managers, I started using WindowMaker very early on and loved the layout and feel of the NextStep interface.

SIDENOTE: I wasn't even sure if WindowMaker existed still but it apparently just had a new release earlier this month (https://www.windowmaker.org/).

I had switched to Debian in about 2000/2001 after fighting my last bout with RPM hell and in about 2005 I switched to XFCE and setup the side panels in a similar fashion to my WindowMaker layout (sidepanel with widgets, right click menu for everything else). While I have moved my widgets to a top left panel, XFCE has remained my DE for almost 20 years. I keep moving my home folder with each hard drive and desktop change with no real issues. The days are gone when I am interested in resolving issues or trying the next shiny feature. I just want a computer that works when I need to use it. I really appreciate the XFCE team for all their work. I have put in the occasional bug report and the response and engagement from the dev team has been pleasant. I have high hopes that the team continues to value the responsive and clean interface of XFCE while making the needed QoL improvements.