I have one of these which is working well with the librem5 however it’s not detecting my monitors correctly .
At the moment both monitors display output correctly but they are mirrored and only one monitor is showing as “unknown display” in settings -> displays
Does anyone know how to rectify this?
You might want to execute sudo dmesg in your L5’s terminal (or sudo dmesg | less and q to exit) to see if you have any relevant kernel messages when you connect the monitors.
It may be that multiple external monitors via a dock is not supported at the current time on the Librem 5, or indeed on Linux at all.
I suggest searching this forum for “MST”.
If you follow your link, see what it says about MacOS support. Maybe that approximates the situation for Linux too.
As in some other post “requested” 
, 4-IN-1: https://www.aliexpress.com/item/1005004428654915.html and 5-IN-1: https://www.aliexpress.com/item/1005001480011636.html (just related examples). Probably based on SM768, yet actually (as usually) no way to find that out (additionally to post #2 here: lsusb might hopefully/indeed help).
@irvinewade, do you think that when USB-C data port on NexDock-360 connected from USB-A port, on linked hubs one, in addition to HDMI, …? Keyboard might work (as it should)?
AFAICS, above devices might be easily explain how your hub HDMI ports actually work (not that I’m sure about that).
EDIT: @andy53, just adding/linking here device with two separate HDMI ports. If you can somehow test this device: https://wvwv.hagibis.com/led-strip-light-usb-c-docking-station-p00232p1.html (U100 Pro and U100 Ultra versions available), please give it a try (besides there are two host inputs), might surprise you pleasantly (but who knows).
EDIT II: CSV-1593 device supports MST mode.
P.S. I have no need for such device, therefore as above.
Not owning a NexDock of any type, I’m going to pass on that one. I do now have a lapdock but I haven’t set it up yet.
I do not have any, although 15.6 inch APC2 might be of my choice (still not available and too early for myself to decide anything, if I’ll get it at all).
Just going to follow up on this in case anyone else has the same problem. At present I have not managed to resolve the issue of the monitors being mirrored however I have purchased one of the docking stations suggested in the comments and will update the thread once it arrives and I have a chance to test it.
Docking station: https://www.amazon.com/dp/B0B1WM9KJJ?th=1
There’s no issue there. Librem 5 can drive one external screen.