I use Kubuntu 20.04 and have GTX 1080 TI. I decided to update videocard drivers and after that I have an issue.
When I try to load the system I faced with black screen (without cursor). I tried to remove drivers and after that I could see all gui interfaces (but couldn’t use some features like nvenc). Then I have tried to reinstall nvidia drivers and again faced with black screen.
I have tried to install different versions of the drivers but always I saw black screen after that.
Every time when I removed drivers I could use my system. But then I have downloaded drivers from nvidia site, not from repository, and tried to install by .sh file. Now I see black screen and can’t remove the drivers by apt remove nvidia*.
Can someone help me with it?

Maybe it will help:

$ sudo modprobe nvidia -vv

modprobe: INFO: ../libkmod/libkmod-module.c:892 kmod_module_insert_module() Failed to insert module '/lib/modules/5.4.0-135-generic/updates/dkms/nvidia.ko': Operation not permitted

modprobe: ERROR: could not insert 'nvidia': Operation not permitted

$ xrandr --listproviders

Can't open display

$ lspci | grep "VGA"

26:00.0 VGA compatible controller: NVIDIA Corporation GP102 [GeForce GTX 1080 Ti] (rev a1)

$ sudo systemctl enable nvidia

Failed to enable unit: Unit file nvidia.service does not exist.

I also tried to add nomodeset in grub but this is can't help.