OK thanks. Then my wild guess is that it's a problem in the upstream driver, and Ubuntu might have some downstream workaround or such. Could you try to boot with video=1024x768 option or such to enforce the resolution? The blank screen could be no hang but just the invalid mode set. Also, if you've already installed TW or Leap 15.3 with nomodeset option (i.e. having a running system), could you try to reboot without nomodeset boot option but with drm.debug=0x1e option, and get the kernel boot log? Reboot again with nomodeset and get the previous kernel log, and upload to Bugzilla.