I wonder if it was a kernel update that caused your issue. Next time you boot up, hit the Esc(ape) key to get to the GRUB menu, then choose 'Advanced options for Zorin', It should list the kernels present on your system. Choose an earlier kernel (it will have a lower number than the current one) and see if you still get a crash.
You can check your installation history by following this guide:
Zorin 18 is a fork of Ubuntu 24.04 and while I had it running on failing drive recently I suffered the 30 second timeout from time-to-time mentioned below:
"To unhide the GRUB menu and alter the timeout in Ubuntu 24.04, follow these steps:
1. Edit the GRUB configuration file: Open the file /etc/default/grub with root privileges:
sudo nano /etc/default/grub
2. Modify the timeout and menu style:
Set GRUB_TIMEOUT_STYLE=menu to ensure the menu is always visible.
Set GRUB_TIMEOUT to your desired number of seconds (e.g., GRUB_TIMEOUT=5 for a 5-second delay).
Optionally, set GRUB_TIMEOUT=0 to boot immediately without a menu, or GRUB_TIMEOUT=-1 to wait indefinitely for user input.
3. Handle the recordfail timeout (critical for Ubuntu 24.04): If the timeout is ignored or defaults to 30 seconds, add or update:
GRUB_RECORDFAIL_TIMEOUT=$GRUB_TIMEOUT
This prevents GRUB from reverting to a 30-second delay after a failed boot.
4. Save and update GRUB: After editing, save the file (Ctrl+O, then Ctrl+X in nano), then run:
sudo update-grub
5. Reboot to test: Reboot your system. The GRUB menu should now appear for the specified timeout duration.
Note : If you're using UEFI and the menu doesn't appear, press Esc during boot to access the menu manually. The GRUB_TIMEOUT_STYLE=menu setting ensures the menu is displayed, but some systems may still require manual key presses.