So, You want try it? Okay. To install the 6.8 Kernel form the Zorin 18 Repo's, type in Terminal:
sudo apt install linux-headers-6.8.0-124-generic linux-image-6.8.0-124-generic linux-modules-6.8.0-124-generic linux-modules-extra-6.8.0-124-generic
When installed, reboot the System. To switch to the Kernel, You have to choose on the GRUB Menu on Start-Up the Option ''Advanced Options'' and there choose the one with the 6.8 Kernel.
If You don't have a GRUB Menu on Start-Up because only Zorin is installed, press Esc or the Shift Key to get it. If that shouldn't work, You can activate the GRUB Menu manually. To do that, boot into Zorin. Open a Terminal and type:
sudo nano /etc/default/grub
Then, You can work on the GRUB Configuration File. There, You should see this Textblock:
To make the GRUB Menu appear, You need to change the Lines 2 and 3 to the Following:
GRUB_TIMEOUT_STYLE=menu
GRUB_TIMEOUT=20
The 20 Value makes that the Grub Menu appears 20 Seconds before it boots in the default. When that isn't enough Time for You, You can use a different Value like 30 or 50. Or when You want to have it as long until You make an Input, You can set it to -1 and then it stays until You have chosen an Option.
When made the Changes, press ctrl+o to save, Enter to confirm and ctrl+x to exit. Then back in the normal Terminal Overview type sudo update-grub to make the Changes affect. Don't forget that! Without it, it will not work.