Sorry for answering so late, but today I was not available.
Great that you had already time to have a look at the log files.
You asked: Is the upload issue related to mobile connectivity or wireless WAN as well?
Answer: Only to mobile connectivity. Only when the traffic goes over mob1s1a1. When I change the network interface order to WLAN connectivity first, there is no problem.
You asked: Have you tried actual file uploads to some servers, emails?
Answer: Yes. I had tested with multiple apps which requires uploads. Including sending an E Mail. Mail with less content can be send, mail with attachment 2 MB, Thunderbird shows error message: closing transmission channel - command timed out.
You asked: Would it be possible to arrange a remote via AnyDesk to check up on your device?
Answer: Yes, that’s mostly everyday possible. Just let me know. I highly appreciate your offer!
Please support in how to test it.
As long as I’m connected to the X11 via mobile connection (SIM1), no upload is possible, which might disturb the AnyDesk session. Or I connect my client with a LAN cable to the X11 and via WIFI (mobile phone hotspot) to the internet. But having two network connections at one client running, I do not know how to control the routing. I tested it now and traffic goes with the LAN cable to the internet. I can access my X11 as well, but I guess no traffic runs over the X11 from my client computer.
Many thanks in advance and looking forward get more insides into the RUT OS.