Thanks for writing here and teaching me about inxi. I am adding the inxi output just in case if it helps someone to solve the issue. I also posted the same question to stack overflow.
https://unix.stackexchange.com/questions/567307/nvidia-driver-doesnt-recognize-the-main-laptop-screen-but-good-with-external-d
As you said that person mentioned bumblebee, and claimed this is a hardware issue. I honestly do not know, but it is just too sad to spend my youth configuring nvidia drivers…
System: Host: bigboi Kernel: 4.15.0-76-generic x86_64 bits: 64 gcc: 7.4.0 Desktop: Gnome 3.28.4 (Gtk 3.22.30)
Distro: Ubuntu 18.04.4 LTS
Machine: Device: laptop System: HP product: HP Pavilion Notebook v: Type1ProductConfigId serial: N/A
Mobo: HP model: 820F v: 82.30 serial: N/A UEFI: Insyde v: F.25 date: 12/12/2016
Battery BAT0: charge: 67.1 Wh 100.0% condition: 67.1/67.1 Wh (100%)
model: Hewlett-Packard Primary status: Full
hidpp__0: charge: 60% condition: NA/NA Wh model: Logitech M570 status: Discharging
CPU: Quad core Intel Core i7-6700HQ (-MT-MCP-) arch: Skylake-S rev.3 cache: 6144 KB
flags: (lm nx sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx) bmips: 20736
clock speeds: max: 3500 MHz 1: 1392 MHz 2: 1493 MHz 3: 1778 MHz 4: 1842 MHz 5: 1915 MHz 6: 1727 MHz
7: 1848 MHz 8: 1698 MHz
Graphics: Card-1: Intel HD Graphics 530 bus-ID: 00:02.0
Card-2: NVIDIA GM107M [GeForce GTX 960M] bus-ID: 01:00.0
Display Server: x11 (X.Org 1.19.6 ) driver: nvidia Resolution: 1920x1080@60.01hz
OpenGL: renderer: Mesa DRI Intel HD Graphics 530 (Skylake GT2)
version: 4.5 Mesa 19.2.8 Direct Render: Yes
Audio: Card-1 Intel 100 Series/C230 Series Family HD Audio Controller driver: snd_hda_intel bus-ID: 00:1f.3
Card-2 NVIDIA Device 0fbc driver: snd_hda_intel bus-ID: 01:00.1
Card-3 Microsoft driver: USB Audio usb-ID: 001-010
Sound: Advanced Linux Sound Architecture v: k4.15.0-76-generic
Network: Card-1: Intel Wireless 7265 driver: iwlwifi bus-ID: 08:00.0
IF: wlo1 state: up mac: <filter>
Card-2: Realtek RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller
driver: r8169 v: 2.3LK-NAPI port: 3000 bus-ID: 09:00.0
IF: eno1 state: up speed: 100 Mbps duplex: half mac: <filter>
Drives: HDD Total Size: 2128.4GB (8.0% used)
ID-1: /dev/sda model: SanDisk_SD8SNAT size: 128.0GB temp: 39C
ID-2: /dev/sdb model: ST2000LM003_HN size: 2000.4GB temp: 37C
Optical-1: /dev/sr0 model: hp DVDRW GUD1N rev: MD00 dev-links: cdrom,cdrw,dvd,dvdrw
Features: speed: 24x multisession: yes
audio: yes dvd: yes rw: cd-r,cd-rw,dvd-r,dvd-ram state: running
Partition: ID-1: / size: 185G used: 151G (87%) fs: ext4 dev: /dev/sdb4
ID-2: /boot size: 454M used: 166M (39%) fs: ext4 dev: /dev/sdb3
ID-3: swap-1 size: 8.00GB used: 0.00GB (0%) fs: swap dev: /dev/sdb5
RAID: No RAID devices: /proc/mdstat, md_mod kernel module present
Sensors: System Temperatures: cpu: 61.0C mobo: N/A
Fan Speeds (in rpm): cpu: N/A
Info: Processes: 323 Uptime: 12:56 Memory: 5045.1/15930.2MB Init: systemd runlevel: 5 Gcc sys: 7.4.0
Client: Shell (bash 4.4.201) inxi: 2.3.56