Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/stm32/stm32l4+/STM32L4Q5/LTCD/L1CR#0x0
LTDC Layer Control Register
Layer Enable
Color Keying Enable
Color Look-Up Table Enable
https://github.com/modm-io/cmsis-svd-stm32