There are many methods and they all safely work.
Let's keep it simple for the moment...
Installing an older kernel:
This is easier, since you likely already have the older kernel in the repositories added to your system.
For example, straight out from terminal:
sudo apt install linux-headers-5.8.0-63-generic linux-modules-5.8.0-63-generic linux-modules-extra-5.8.0-63-generic linux-image-5.8.0-63-generic
Or
sudo apt install linux-headers-5.11.0-27-generic linux-modules-5.11.0-27-generic linux-modules-extra-5.11.0-27-generic linux-image-5.11.0-27-generic
sudo apt install linux-headers-5.13.0-28-generic linux-modules-5.13.0-28-generic linux-modules-extra-5.13.0-28-generic linux-image-5.13.0-28-generic
You can also download the four needed packages from the Mainline kernel webpage and install all of them at once using dpkg. I can detail this method, if needed.
Installing a newer kernel:
To boot from a different kernel than the one you are using:
At boot, tap on the esc or tab key to bring up the Advanced Options for Zorin grub menu - arrow key to the kernel you wish to boot into and enter to select it.
You can verify that it worked by reaching the desktop, then running
uname -r
in terminal.