Unable to boot after installing Nvidia drivers (v 455) in Ubuntu 20.10 for RTX 3070 card

After installing the proprietary Nvidia drivers (version 455) under Ubuntu 20.10, I am unable to reboot into my system. I simply get a black screen with a blinking cursor, and then absolutely nothing happens.

I have been able to “fix” my install by running a live USB, chrooting, uninstalling the drivers and reinstalling the default Nouveau drivers.

I am using the “Additional Drivers” GUI method of installation from within Ubuntu.

Since absolutely nothing happens except for a blinking cursor, I suspected that there might be some boot issue due to secure boot. But looking at my settings, I believe secure boot is disabled. It doesn’t state it is enabled anyway, it’s greyed out with “setup”. I also don’t have any keys that I can see, which seems to be the way to disable secure boot. “Other OS” is also selected rather than Windows.

Another issue I thought of would be that the driver is too old to support an RTX 3070. But checking the build of the drivers on launchpad for 20.10, the release notes literally state that they have 3070 support.

I have no clue what else to do, other then install Windows (which I really don’t want to do).

My hardware:

Mobo: Asus ROG strix b450 f
CPU: AMD 3900X
GPU: Nvidia 3070 (Zotac twin edge OC white)