Currently This attribute is using the default rds kms key and also there is a resource of kms creation for aurora and rds so if you create aurora then it will create a CMk for you and by default it will use rds and cannot be changed because there is no variable for performance attribute and there is no use of that CMK which is being created by module so either remove that kms key creation for aurora and use target key arn of default rds kms with data lookups and make a variable of performance attribute and also add a condition so that anyone wants to override this value with its own CMK can do it as well.
Second option is to remove data lookups for defult rds kms key and to make performnace attribute conditional like if this value is null then it will use the CMK key which is created by module and if its not null then definitely it will be using that Key whichever enduser have provided
Currently This attribute is using the default rds kms key and also there is a resource of kms creation for aurora and rds so if you create aurora then it will create a CMk for you and by default it will use rds and cannot be changed because there is no variable for performance attribute and there is no use of that CMK which is being created by module so either remove that kms key creation for aurora and use target key arn of default rds kms with data lookups and make a variable of performance attribute and also add a condition so that anyone wants to override this value with its own CMK can do it as well.
Second option is to remove data lookups for defult rds kms key and to make performnace attribute conditional like if this value is null then it will use the CMK key which is created by module and if its not null then definitely it will be using that Key whichever enduser have provided