Voting for this issues since it's really important to us, since we are using hibernate.hbm2ddl.auto=update
And it's really not up-to-date not to support UNICODE.
As a workaround here is the pointer on how to inject custom dialects:
https://docs.jboss.org/hibernate/orm/5.3/userguide/html_single/Hibernate_User_Guide.html#portability-dialectresolver
Or read this: https://blog.exxeta.com/java/2016/03/23/dynamically-resolve-hibernate-database-dialect/