Hi
We at Meta Store Support would be glad to help you get this problems resolved, and back to enjoying your new Quest 2.
You can try the following general suggestions first to see if they help with your grey screen issue;
1. Try removing any unsupported third-party accessories that may affect boot (such as external battery packs, accessories that plug into the USB-C port, etc.)
2. Check for sufficient battery charge, Ensure the headset is charged by allowing it to charge for at least 2 hours.
3. Try using the software update tool to update and check firmware of device- Software Update Tool.
4. Hard Reboot the headset
If the problem persists then please let us know, and we can look into further troubleshooting for you.
Thanks very much.