This states that you have added a repository multiple times to your sources.
This may have happened if you repeated a guides instructions or were uncertain as to whether a repository was added and sent the command to add it again.
To resolve this, elevate to root
sudo -i
Launch the file manager:
nautilus
Navigate to the Sources.list.d directory. In the left pane, select "Other locations." In the right pane, select "Computer". This will take you to top level of root.
Now you will see the /etc directory. Open it. Then the directory /apt and finally /sources.list.d. Remember, you are opening the folder, not the source.list file.
In this folder, look for the Duplicate Entries for XanMod and right click and remove them. Once done, close the elevated file manager and terminal.
You may want to remove them all... Let's look at that below:
The DKMS Nvidia Driver build is dealing with a mismatch in the modules. This can cause you graphical errors and is related to the non-standard XanMod kernel you are trying to install.
I imagine that you are trying to resolve a different issue by installing the later XanMod kernel - but as you can see in this error; you may be jumping out of the frying pan and into the fire.
You may be better off removing the Xanmod kernel and all of the Xanmod repositories.
If you still need the later LTS kernel, though - instead, install the tuxinvader kernel.
In terminal, run:
sudo add-apt-repository ppa:tuxinvader/lts-mainline
sudo apt update && sudo apt install linux-generic-6.02
That's it. That is all that is needed and that will install the 6.2 kernel. You must reboot to boot into it.
Lastly;
On this one, please see this thread for understanding and resolving the "Possible Missing Firmware" warning: