This is to fix Sleep on macOS Tahoe 26.5.2
There's a glitch in sleep mode where if you enter sleep mode, minutes later the Mac will turn on and show a grey screen. This is caused by a corrupted driver with OpenCore and your AMD GPU (if you have a Intel GPU, this will still work if needed).
If you need sleep mode, Launch Terminal and disable "hibernation" with the commands sudo pmset -a hibernatemode 0 and sudo pmset -a autopoweroff 0. Then, Power Nap (you can also use System Settings then Energy), sudo pmset -a autopoweroff 0 and disabling standby delay sudo pmset -a standby 0.
After, you need to rebuild and Install OpenCore on your Mac and reboot. Try using sleep mode for at least 5 minutes before waking your Mac and if your Mac no longer shows a grey screen, you have successfully fixed this issue however, if the issue isn't fixed, try resetting your NVRAM.