I can see quite a few graphics-related errors in your log but can't tell what type of GPU it is and also the log is truncated.
Please run:
lspci -k > lspcik.txt journalctl -b0 > journal.txt journalctl -b-1 > prevjournal.txt xrandr > xrandr.txt # while both monitors are plugged in
and attach the resulting text files here.
I can see quite a few graphics-related errors in your log but can't tell what type of GPU it is and also the log is truncated.
Please run:
lspci -k > lspcik.txt
journalctl -b0 > journal.txt
journalctl -b-1 > prevjournal.txt
xrandr > xrandr.txt # while both monitors are plugged in
and attach the resulting text files here.