Ubuntu 20.04 LTS Fails to boot on Lenovo Flex 3-1480 laptop

I've been running Ubuntu 20.04 LTS since May 2020. On Nov 12 I did a
system update. The update requested a reboot. The system never
completed the reboot.

NOTE: Your guide lines say to select "linux" as the package if booting
fails even in the "recovery"mode. So I did. Even though my tests indicate
that the problem is NOT actually in the kernel. Recovery mode did fail
quite a few times last year.

Summary of debugging attempts:
-----------------------------

There is some hardware dependency, as my Acer Aspire E5-576 laptop
boots every time, while my Lenovo Flex 3-1480 laptop boots poorly,
less that 50% of the time. In recovery mode, it boots much better,
but not nearly all of the time.

Linux Mint 20.1 also boots very poorly on Lenovo Flex 3-1480 laptops. likely, many other distros derived from Ubuntu 20.04 boot poorly. Other
hardware platforms re likely to have this issue.

It is NOT GRUB. Other distros boot from GRUB. Ubuntu 15.10, Ubuntu
18.10, and MX Linux 19.3 boot every time from GRUB. Additionally,
Ubuntu 20.04 fails to boot from rEFInd.

It is NOT the kernel. Old kernels fail to boot. These kernels booted
fine before the update.

It is NOT systemd. I suspected systemd, but when I attempted to
isolate the problem to systemd, I failed.

I have spent many, many hours over many months attempting to isolate
this problem to a particular module. I failed. Good luck.

Details of debugging attempts:
-----------------------------

The latest kernel on Nov 12, 2020 was 5.4.0-54-generic. I'm not sure
if this was installed by that update or not. I tied to boot earlier
kernels. Neither 5.4.0-53-generic nor 5.4.0-52-generic booted. I
tried booting -53- in recovery mode. That worked, but the screen
resolution is very low, making my large high resolution monitor
relatively useless.

I have two computers with Ubuntu 20.04 installed. The Lenovo Flex
3-1480 fails to boot reliably, less than 50% success. The Acer Aspire
E5-576 boots every time.

Over the next few months, I tried many things. I installed rEFInd boot
loader. Ubuntu 20.04 still failed to boot. Ubuntu 15.10 and Ubuntu
18.10 still boot just fine from either GRUB of rEFInd.

I had initially installed Ubuntu 20.04 on a USB Flash drive. Some
claim a relatively short life for USBs used that way, so I installed
Ubuntu 20.04 on my HDD. That booted no better than the USB install.

In mid January, I installed Linux Mint 20.1. This is a close
derivative of Ubuntu 20.04. Linux Mint 20.1 boots no better than
Ubuntu 20.04.

In February, I installed MX Linux 19.3 This boots every time! MX
Linux installed a separate copy of GRUB. From the EFI boot menu, I can
select either MX Linux GRUB or Ubuntu GRUB. From either GRUB, both
Ubuntu 20.04 and Linux Mint 20.1 boot badly. From either GRUB, Ubuntu
15.10, Ubuntu 18.10 and MX Linux 19.3 boot every time.

In mid April 2021, I attempted to demonstrate that systemd was the
problem. I reinstalled Ubuntu 20.04 from the Apr 2020 image. I
specifically did NOT update. With the Ubuntu 20.04 April 2020 image I
booted 18 times NO failures. (systemd version was 245.4-4ubuntu3)

I Upgraded systemd to the latest version: 245.4-4ubuntu3.6. NO OTHER
updates! All else is April 2020 image. Booted 10 times NO failures.
This demonstrates that systemd is not the problem.

I did a full system upgrade on 2021 Apr 16. In the next few days:
  Booted in normal mode 18 times, 14 failures
  Booted in recovery mode 7 times, 0 failures
  Boot failure rate 14/25 = 56%

--------------------------
Other stuff you requested:

1005 asteroid ~ lsb_release -rd
Description: Ubuntu 20.04.2 LTS
Release: 20.04

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: linux-image-5.8.0-50-generic 5.8.0-50.56~20.04.1
ProcVersionSignature: Ubuntu 5.8.0-50.56~20.04.1-generic 5.8.18
Uname: Linux 5.8.0-50-generic x86_64
ApportVersion: 2.20.11-0ubuntu27.16
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: ubuntu:GNOME
Date: Thu Apr 22 20:30:42 2021
InstallationDate: Installed on 2021-04-16 (6 days ago)
InstallationMedia: Ubuntu 20.04 LTS "Focal Fossa" - Release amd64 (20200423)
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: linux-signed-hwe-5.8
UpgradeStatus: No upgrade log present (probably fresh install)