Should I flatten / denormalize messages in DDD in ksqlDB?

Should I flatten / denormalize messages when using Domain Driven Design (DDD) in ksqlDB, or is having aggregates in an array of structs on the aggregate root acceptable (and performant)?

I’ve posted the question on StackOverflow if you’d prefer to answer there: Should we flatten / denormalize messages in DDD in ksqlDB? - Stack Overflow

Thanks,
Jim