I didn’t see anyone else with a C2 complaining about the problems you are describing, so assume it is going to work properly in CoreELEC.
As I don’t own a C2, I can’t test it.
Because everybody’s setup is different (your old TV could be a problem), the best way would be to use a spare sd card, install CE onto it and test it for yourself.
If it doesn’t work as expected, you can always switch back to your old sd card with LE on it.
Btw…Amazon Prime and Netflix are being decoded in software, because of some restrictions in the widevine library in conjunction with these providers.