Just throwing out more ideas:
Is there a CPU spike on the VPS?
Anything weird about Wireguard on either end? Using kernel mode WG everywhere and not a user mode version, right?
As a test I would be inclined to try a very small mtu to see if it makes a difference. 1280 is a failsafe that I use when on unknown networks and trying to wg out.
Maybe try with a smaller packet size, like 1KB which I think is -l 1K
Are you specifying bandwidth (-b) on the iperf UDP test? It defaults to 1M if I recall correctly, which would explain the result.
If not, try -b 10M or -b 0 for unlimited (the behavior used for TCP).
I’m doing this on a couple of machines. Only running NFS, Plex (looking at a Jellyfin migration soon), Home Assistant, LibreNMS and some really small other stuff. Not using VMs or LXC due to low-end hardware (pi and older tiny pc). Not using containers due to lack of experience with it and a little discomfort with the central daemon model of Docker, running containers built by people I don’t know.
The migration path I’m working on for myself is changing to Podman quadlets for rootless, more isolation between containers, and the benefits of management and updates via Systemd. So far my testing for that migration has been slow due to other projects. I’ll probably get it rolling on Debian 13 soon.
I’m using Mikrotik and Ruckus. Would recommend both. I like that they are both at the level of reliability that I don’t think about them at all for months at a time. I update quarterly or less and they require no other attention from me. They also work well with my centralized data collection and alerting via LibreNMS.
OPNSense would be high on my list of alternatives when I reevaluate next time. And all Mikrotik would be a good option for me as well. Their Wi-Fi gear is not as strong as Ruckus or Ubiquiti, but they are super solid.
The Unifi ecosystem is a bit too centralized for me. I don’t want to create an account in order to use the hardware.
Same here. It was already a little bit concerning that I was relying on a smaller fork to get syncthing on Android. It was on my to do list to figure out options. Now it’s at the top of the list, and I’m not doing updates for the time being on Android. That’s almost the entirety of my reliance on syncthing - phone to PC sync. I don’t really need it that much for sync between PCs.