After watching the staff, I understood why PD Solfa focused on Jena.

‌
As a PD, I think Jena's character could appear quite charming.
If he could draw out Jena's charm through his own ability,
I imagine he would have felt a great sense of accomplishment as a PD.
In the end, he made her a success.
I don't know his exact thoughts,
but I get the feeling that after making Jena's character successful,
he must have felt truly proud as a PD.