Ubuntu 18.04 black screen at startup after installing a driver for MX450/Cannot adjust brightness/No 2nd monitor detected through HDMI

I newly installed Ubuntu 18.04 (This specific version is required for some robotics application I am using so I cannot upgrade the Ubutnu version). After installing Nvdia driver, the system is stuck at black screen and I cannot get to the normal login menu. I tried swtiching to several different versions of the proprietary drivers (under Software & Updates as in the screenshot below) but things were the same.

I could boot through recovery mode and here are some information I gathered from it. When I run nvidia-settings, I get this:

ERROR: NVIDIA driver is not loaded
ERROR: Unable to load info from any available system

When I run nvidia-smi,
NVIDIA-SMI has failed because it couldn't communicate with the NVIDIA driver. Make sure that the latest NVIDIA driver is installed and running.

I get nvidia when I run sudo prime-select query.

I attached the bug report as well that I generated on the recovery mode.

nvidia-bug-report.log.gz (115.1 KB)

I’m using Lenovo Ideapad 5i and my system set up is as the following:
Intel Core i7-1165G7 @2.8GHz x 8
Nvidia GeForce MX450 2GB
GNOME 3.28.2

Additionally, I found that I cannot adjust the brightness and I cannot connect to the 2nd monitor through HDMI. After googling, I suspect this might be related to the driver issue as well so I just combined the questions. Please let me know if I should provide additional information and/or I should separate my questions.

Thank you so much in advance!