Send an email to leave approver of each department

I have several departments in my company, every time an employee wants to apply for leave, they have to apply first to the superior of each respective department

First case: I didn’t create a role for the user as leave approver

second case: I created a leave approver in each department

the problem is:

When an employee wants to apply for leave, the notification email is not sent to the leave approver that I set in each department

indication:

when I set the leave approver in the user section, all employees’ leave applications will be sent to any leave approver and I don’t want that

what I expected:

How to set up this workflow so that emails are still sent to each leave approver

thank you