I updated Rocky from 6.12.0-124.49 to 124.56. The two kernels fit boot space, but when I restantes my pc I got the following message

I would poweroff and try starting again. I periodically have hangs on reboots after new kernel installs both with Rocky 9 on real hardware and Rocky 10 in a vm. My vm had no issues with that kernel upon reboot. If this presists try booting back to the prior kernel.