I'm not sure whether Chromeboxes boot using syslinux or EFI boot, but the boot menu is in the syslinux.cfg file (for syslinux) or a file under the EFI directory for EFI. Both files are human readable and you should be able to edit the boot menu to change the default option from install to live, then you don't need to hit a key. You can also place "textmode" somewhere in the list of boot params and the box will boot to a text console instead of Kodi. That's sometimes useful for narrowing down whether it's the kernel that causes the problem or not. If the OS is usable then the issue probably lies in the userspace side of the graphics stack and if you manually start Kodi via its systemd service while also accessing via SSH to tail logs, you might get some clues. Adding "ssh" to boot params forces the daemon to start.
Got back from travel, and had a chance to do this. Appended "SSH" to the "run" option to boot the 12.2 installer on USB using RAM for storage, I was able to SSH in. The internal SSD is sdb and on in the .kodi/temp/kodi.log I find:
2025-10-13 17:09:20.550 T:1099 info <general>: CAESinkALSA::Initialize - Attempting to open device "hdmi:CARD=HDMI,DEV=0"
2025-10-13 17:09:20.571 T:1099 info <general>: CAESinkALSA::Initialize - Opened device "hdmi:CARD=HDMI,DEV=0,AES0=0x04,AES1=0x82,AES2=0x00,AES3=0x00"
2025-10-13 17:09:20.572 T:1099 info <general>: CAESinkALSA::InitializeHW - Your hardware does not support AE_FMT_FLOAT, trying other formats
2025-10-13 17:09:20.572 T:1099 info <general>: CAESinkALSA::InitializeHW - Using data format AE_FMT_S32NE
2025-10-13 17:09:25.483 T:1087 info <general>: Saving exitCode 66
2025-10-13 17:09:26.069 T:1087 info <general>: Quitting due to POSIX signal
2025-10-13 17:09:26.086 T:1087 info <general>: Stopping the application...
2025-10-13 17:09:26.086 T:1087 info <general>: Stopping player
2025-10-13 17:09:26.086 T:1087 info <general>: Storing total System Uptime
2025-10-13 17:09:26.086 T:1087 info <general>: Saving settings
2025-10-13 17:09:26.090 T:1087 info <general>: Saving skin settings
2025-10-13 17:09:26.090 T:1087 info <general>: Stopping all
2025-10-13 17:09:26.090 T:1087 info <general>: ES: Stopping event server
2025-10-13 17:09:26.155 T:1115 info <general>: ES: UDP Event server stopped
2025-10-13 17:09:26.198 T:1122 error <general>: Exception ignored on calling ctypes callback function
2025-10-13 17:09:26.198 T:1122 error <general>: :
2025-10-13 17:09:26.198 T:1122 error <general>: <function Connection.add_filter.<locals>.wrap_function at 0x7f79e0df70a0>
2025-10-13 17:09:26.198 T:1122 error <general>:
2025-10-13 17:09:26.198 T:1122 error <general>: Traceback (most recent call last):
2025-10-13 17:09:26.198 T:1122 error <general>: File "/usr/lib/python3.11/site-packages/dbussy.py", line 2616, in wrap_function
2025-10-13 17:09:26.199 T:1122 error <general>: File "/usr/lib/python3.11/site-packages/ravel.py", line 2036, in _message_interface_dispatch
2025-10-13 17:09:26.199 T:1122 error <general>: File "/usr/share/kodi/addons/service.libreelec.settings/resources/lib/dbus_bluez.py", line 70, in Release
2025-10-13 17:09:26.199 T:1122 error <general>: NotImplementedError
2025-10-13 17:09:26.199 T:1122 error <general>: :
2025-10-13 17:09:26.199 T:1122 error <general>:
2025-10-13 17:09:26.199 T:1122 error <general>:
2025-10-13 17:09:26.270 T:1087 info <general>: CWSDiscoveryListenerUDP::Stop - Stopped
2025-10-13 17:09:26.270 T:1087 info <general>: stopping zeroconf publishing
2025-10-13 17:09:26.280 T:1113 info <general>: SETTINGS: stop_service # ## LibreELEC Addon ## STOP SERVICE DONE !
2025-10-13 17:09:26.280 T:1127 info <general>: SETTINGS: run # updateThread Stopped
2025-10-13 17:09:26.280 T:1128 info <general>: SETTINGS: run # Received exit
2025-10-13 17:09:26.692 T:1087 info <general>: Application stopped
2025-10-13 17:09:27.276 T:1087 info <general>: AddOnLog: peripheral.joystick: Disabling joystick interface "linux"
2025-10-13 17:09:27.276 T:1087 info <general>: ADDON: Dll Destroyed - Joystick Support
2025-10-13 17:09:27.276 T:1087 info <general>: unload skin
2025-10-13 17:09:27.291 T:1087 info <general>: Unloaded skin
2025-10-13 17:09:27.321 T:1087 info <general>: unload sections
2025-10-13 17:09:27.323 T:1087 info <general>: CWSDiscoveryListenerUDP::Stop - Stopped
2025-10-13 17:09:27.934 T:1087 info <general>: Exiting the application...
This appears to be choking after attempting to initialize graphics hardware. Interestingly the 12.2 installer booting from USB boots in to it's GUI just fine...
Do you use the same BIOS settings in both boxes?
Yes. There are practically none.