Just our two cents.
It’s not a decision by CoreELEC to get such issues.
It’s Amlogic introduced a new security update in bootloader and firmware. New and old firmware is just not compatible anymore. This is since SoC SC2, T7 and S5. SoC before don’t use TEE at all so aren’t affected.
There is no issue for Android as they get delivered compatible, bootloader and firmware.
So if you got a device not compatible with the new security system it’s best to stay on old CoreELEC version what is still compatible with it.
It’s mostly CE-NE.
If you don’t care about AV1 or VC-1 you just can skip this fact. Other decoders are implemented long enough to still work fully with old firmware as well.