Initramfs hangs/crashes on boot with any installed Nvidia driver

Hello,
I own a Dell laptop with the following hardware:

    RTX 2060 mobile (rev a1, 10de:1f11)
    Desktop-grade i9-9900k
    24Go RAM 2400MHz
    NVME storage
    Secure Boot disabled
    BIOS up-to-date

I reinstalled recently from scratch my Ubuntu. The nouveau driver works well with Ubuntu 20.04 and Linux kernel 5.8.0. However, if I install any Nvidia driver (450, 460, 465), from Canonical, graphicsdrivers PPA, or Nvidia CUDA repository, the initial ram filesystem fails to load at boot time (it is stuck before entering the “booted” state), without any errors on screen. If I try the recovery boot mode, with debug added to the kernel options, I only get as message

    Loading initial ramdisk…

Adding nomodeset, or running prime-select intel on chroot do not change anything.

Moreover, I cannot boot from any live Ubuntu using kernel >= 5.8.0 (including Ubuntu 21.04). Sometimes, I can make Ubuntu working by installing linux-modules-nvidia-460-generic-hwe-20.04 but at the next kernel update from unattended-upgrades it gets broken again. I have no specific warnings or errors when installing the Nvidia driver.

I am troubleshooting my installation using a chrooted environment from an old live USB after installing the Nvidia driver, and letting the laptop freezing at the next reboot. I attached the results of nvidia-bug-report in this specific environment. I also opened an issue on the Nvidia forum : https://forums.developer.nvidia.com/t/ubuntu-kernel-5-8-nvidia-driver-makes-initramfs-crashes-on-boot/175465

In the past, my laptop was working on Ubuntu 20.04 with 5.4 kernels and Nvidia driver 450 without this problem. I also tested a live USB Manjaro 21.0.2 (kernel 5.10) with Nvidia driver 460, and there are no issues.

---

$ lsb_release -rd
Description: Ubuntu 20.04.2 LTS
Release: 20.04

---

What I expect : Initramfs loading kernel at boot
What happenned : Initramfs stuck before loading kernel

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: KDE
Date: Sun Apr 25 11:37:43 2021
InstallationDate: Installed on 2021-03-27 (28 days ago)
InstallationMedia: Kubuntu 20.04.2.0 LTS "Focal Fossa" - Release amd64 (20210209.1)
SourcePackage: linux-signed-hwe-5.8
UpgradeStatus: No upgrade log present (probably fresh install)