Version as of May 2024: v4.6.1-1

https://www.darktable.org/install/

echo 'deb http://download.opensuse.org/repositories/graphics:/darktable/xUbuntu_22.04/ /' | sudo tee /etc/apt/sources.list.d/graphics:darktable.list
curl -fsSL https://download.opensuse.org/repositories/graphics:darktable/xUbuntu_22.04/Release.key | gpg --dearmor | sudo tee /etc/apt/trusted.gpg.d/graphics_darktable.gpg > /dev/null
sudo apt update
sudo apt install darktable

alternative repo:

sudo add-apt-repository ppa:ubuntuhandbook1/darktable
sudo apt update
sudo apt install darktable

other repos:
https://software.opensuse.org/download.html?project=graphics:darktable&package=darktable