Can't go back to older nvidia driver on Ubuntu 20.04


I’m experiencing some slowdowns (10% drop) after updating from driver435 to driver460. I’m on Ubuntu 20.
I wanted to go back to driver435, and when I want to rollback, it says:

  • nvidia-driver-435 : Depends: nvidia-driver-455 but it is not going to be installed

So I don’t understand how it’s possible that an older driver depends on a newer driver.
Do you have an idea on how to use the nvidia-driver-435 on Ubuntu 20.04 please?

ps: I’ve already tried this: apt - Ubuntu 18.10 : How can I install a specific NVIDIA drivers version? - Ask Ubuntu

Thanks for any answer!

Ok I solved it. I had to also run

sudo apt purge libnvidia*

Then I could reinstall older drivers from here Ubuntu – Details of package nvidia-driver-435 in focal