Well, feature requests and bug reports are somewhat intertwined these days. Hence ‘wishlist’ tags in bug tracking systems and so on. As you say, it would be desirable for the system to offer some assistance even in bad situations like these. It’s strange that they removed displayconfig-gtk without a replacement available, it must have had some serious flaws. It used to get run when X starts in failsafe configuration.
Anyway, It would be interesting to see what result the OP gets with a different cable. Also, since the intel driver is supposed to use kernel modesetting now, there could be some output of interest in dmesg.