SSH and WebUI not accessible after couple days

For all future readers:
So! After a while I can confidently say the issue is gone. Current uptime 11 days.

Now as to what was the issue was exactly I cannot say for sure, since I got rid of some plugins after all, which I didn't need.

But I have a strong suspicion, that the ultimate solution was as simple as disabling the c-states (and checking that the RAM is running at the correct speed, as suggested by JorgeB's guide.

This since my current config, which lasted 11 days pretty much identical to the previous setup.

The only differences being some uninstalled plugins, a re-flashing of Unraid and the removal of some plugins. 

Additionally I came across the RTL8168 Drivers from community applications, which I also installed, however I has worked reliably for 3 days without I too.

Otherwise, same Hardware, Docker Containers and with neither pcie_aspm=off nor pci=noaer.

So if anyone else comes across this issue, I would recommend you to:

1. Follow JorgeB's guide on finding the correct RAM speed and disabling the c-states.
2. Additionally, it makes sense to install the RTL Drivers (pick the right one for your system).
3. If all that doesn't resolve the issue, try setting pcie_aspm=off or pci=noaer. 

Thanks for all the help along the way! Hope this helps if someone else has the same issue.