I’ve had Diamondbrite on a BMW in the past – it was ok.
i think the protection offered by modern ceramic coating is more durable and longer lasting.
My RS was done using Gyeon MOHS + and it looks amazing.
I think if you do that then for the best possible protection apply a PPF such as Xpel you will have done as much as you can – but you will be looking upwards of £1500 for both.