This looks like a bug in Hibernate ORM:

• In Hibernate ORM 5.x, the “blob” JDBC type was translated to “blob(<column length>)” in the schema definition
• In Hibernate ORM 6, the column length is ignored: https://github.com/hibernate/hibernate-orm/commit/a9d1035806014fb2804b2f661692e065c32619a6#diff-b569b438f401c092432d54437122c7f260fc7bc5f3d57939411132fcdcf5e63eL147-R147