Hello,
I have a Librem 15v4 that I am successful in connecting a single external 4k display. However, I was wondering if it’s possible to connect a second for dual monitors? If so, any guidance would be most appreciated. I couldn’t find anything solid while searching online.
Cheers.
No, I’m afraid that’s not possible, the L15 only supports one external display via HDMI.
Cheers
nicole
Ah ok thanks. I’m guessing that’s a hardware limitation of the chipset?
Not really the chipset, rather the plugs available 
The type-C port does not support alt-mode video output so the HDMI is the only external video interface available. And HDMI does not support daisy chaining like DisplayPort would. So there is simply no other connector to attach a second display to.
The only rather theoretical way would be a USB video adapter, but these are rather expensive, slow and there are only very few supported by Linux.
Cheers
nicole
Gotcha, appreciate the clarification 
You could try DisplayLink as a compromise. But there are limits and drawbacks (closed protocol, partly closed source/ blob, didn’t work with wayland, no idea how it works with bullseye).
Update: