[modeset + nvidia + lightdm] MSI GP72 laptop screen blank after reboot

connected to external monitor. After a reboot the laptop screen is blank. Can't find a consistent way to get it back.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: xorg 1:7.7+19ubuntu7.1
ProcVersionSignature: Ubuntu 5.4.0-48.52~18.04.1-generic 5.4.60
Uname: Linux 5.4.0-48-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
.proc.driver.nvidia.capabilities.gpu0: Error: [Errno 21] Is a directory: '/proc/driver/nvidia/capabilities/gpu0'
.proc.driver.nvidia.capabilities.mig: Error: [Errno 21] Is a directory: '/proc/driver/nvidia/capabilities/mig'
.proc.driver.nvidia.gpus.0000.01.00.0: Error: [Errno 21] Is a directory: '/proc/driver/nvidia/gpus/0000:01:00.0'
.proc.driver.nvidia.registry: Binary: ""
.proc.driver.nvidia.suspend: suspend hibernate resume
.proc.driver.nvidia.suspend_depth: default modeset uvm
.proc.driver.nvidia.version:
 NVRM version: NVIDIA UNIX x86_64 Kernel Module 450.66 Wed Aug 12 19:42:48 UTC 2020
 GCC version: gcc version 7.5.0 (Ubuntu 7.5.0-3ubuntu1~18.04)
ApportVersion: 2.20.9-0ubuntu7.17
Architecture: amd64
CompositorRunning: None
Date: Mon Oct 5 15:50:47 2020
DistUpgraded: Fresh install
DistroCodename: bionic
DistroVariant: ubuntu
DkmsStatus:
 nvidia, 450.66, 5.4.0-47-generic, x86_64: installed
 nvidia, 450.66, 5.4.0-48-generic, x86_64: installed
ExtraDebuggingInterest: Yes
GraphicsCard:
 Intel Corporation Device [8086:591b] (rev 04) (prog-if 00 [VGA controller])
   Subsystem: Micro-Star International Co., Ltd. [MSI] Device [1462:11c9]
   Subsystem: Micro-Star International Co., Ltd. [MSI] GP107M [GeForce GTX 1050 Mobile] [1462:11c9]
InstallationDate: Installed on 2020-06-03 (123 days ago)
InstallationMedia: Ubuntu 18.04.4 LTS "Bionic Beaver" - Release amd64 (20200203.1)
MachineType: Micro-Star International Co., Ltd. GP72 7RD
ProcEnviron:
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
 TERM=xterm-256color
 LANGUAGE=en_GB:en
 PATH=(custom, no user)
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.4.0-48-generic root=/dev/mapper/ubuntu--vg-root ro nouveau.modeset=0
SourcePackage: xorg
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 03/23/2018
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: E1799IMS.324
dmi.board.asset.tag: Default string
dmi.board.name: MS-1799
dmi.board.vendor: Micro-Star International Co., Ltd.
dmi.board.version: REV:1.0
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: Micro-Star International Co., Ltd.
dmi.chassis.version: N/A
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrE1799IMS.324:bd03/23/2018:svnMicro-StarInternationalCo.,Ltd.:pnGP727RD:pvrREV1.0:rvnMicro-StarInternationalCo.,Ltd.:rnMS-1799:rvrREV1.0:cvnMicro-StarInternationalCo.,Ltd.:ct10:cvrN/A:
dmi.product.family: GP
dmi.product.name: GP72 7RD
dmi.product.sku: 1799.3
dmi.product.version: REV:1.0
dmi.sys.vendor: Micro-Star International Co., Ltd.
version.compiz: compiz N/A
version.libdrm2: libdrm2 2.4.101-2~18.04.1
version.libgl1-mesa-dri: libgl1-mesa-dri 20.0.8-0ubuntu1~18.04.1
version.libgl1-mesa-glx: libgl1-mesa-glx 20.0.8-0ubuntu1~18.04.1
version.nvidia-graphics-drivers: nvidia-graphics-drivers-* N/A
version.xserver-xorg-core: xserver-xorg-core N/A
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A
version.xserver-xorg-video-ati: xserver-xorg-video-ati N/A
version.xserver-xorg-video-intel: xserver-xorg-video-intel N/A
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau N/A
xserver.bootTime: Mon Oct 5 15:30:42 2020