While we are now able to determine non-specific names in a more granular way, through the ImplicitNamingStrategy, than before it seems that some code is still using their own implementation.
I have found at least one occurrence where this is the case:

org.hibernate.mapping.Constraint contains still some generateName methods which are essentially doing the same as the naming strategy.

In particular Primary and (some) UniqueConstraints are not running through the ImplicitNamingStrategy.

It seems that ForeignConstraints are directed "correctly" to the naming strategy, but I did not investigate deeply why this is the case.

This means that we currently do not have a way to interfere with primary and (some) unique constraints name generation. Is that correct?