Hi @Francesco Cesareo , welcome to Microsoft Q&A forum.
You are right in mentioning that @partitionkey annotation takes precedence when defined. Also the same article mentions that partitionKeyPath should only be used to support nested partition key path. For general partition key support, use the @PartitionKey annotation.
So if you dont have the nested key path, you can choose to use @partitionkey annotation.
Please let us know if this helps or else we can discuss more on this.