[Solved] Unhelpful error message when unable to enable a second monitor

[vindico]

Primary monitor decided to stop working this morning, works fine on windows however. Display settings picks up both monitors but one isn't enabled (https://i.imgur.com/YnuIrIw.png). Trying to enable it results in this error message: https://i.imgur.com/wqvnfj2.png which is ... extremely unhelpful.

Latte thinks both screens are the same and has doubled up my docks on the single remaining screen.

Have updated drivers (and everything else), no luck there.

Xrandr throws some errors that seem like they should be useful but I don't know how to interpret them:

1. xrandr: Output DP-0 is not disconnected but has no modes (When trying to add the monitor)
2. screenlayout.auxiliary.InadequateConfiguration: Smallest mode too large for virtual. (When trying to enable it)

Xrandr output:

DP-1 disconnected (normal left inverted right x axis y axis)
DP-2 disconnected (normal left inverted right x axis y axis)
DP-3 disconnected (normal left inverted right x axis y axis)
DP-4 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 531mm x 299mm

Anyone point me in the right direction?

[vindico]

Somewhat solved my own issue - laptop display cable plugged into the same monitor was the issue. Once unplugged the monitor is working again, which is annoying because that monitor has been switching between work laptop and home system fine for ages