Kernel version 6.8 broke suspend ($ systemctl suspend) for me. I run two machines with near identical setups. I upgrade my "preview" machine first before updating my primary machine to test for defects.
If I boot from kernel version 6.5, suspend works fine. Hold shift while your machine is booting and the grub menu will allow you to select a different kernel version.
If I boot from kernel version 6.5, suspend works fine. Hold shift while your machine is booting and the grub menu will allow you to select a different kernel version.