Not able to debug notification service extensions

Hi,
I am using iOS service extensions to modify notification content. I did all the process required to configure the extension. My extension methods don't get called when I try sending push.
Also, debugger doesn't get attached to the service extension :

here's my check list :
Deployment target for both app and service extensions are same i.e., iOS 14.4

I tried :
Setting breakpoint in the extension
Select Debug / Attach to Process by PID or name
Entered the name of the extension target
Triggered the push notification
(still no luck)

payload format :

let mesg = {
                notification: {
                    title: "New  Message",
                    body: "You have new message"
                },
                data: {
                    commentId: commentId,
                    userId: userid,
                    comment: comment,
                    projectId: projectId,
                },
                apns: {
                    payload: {
                        aps: {
                            "mutable-content": 1,
                            alert: ""
                        }
                    }
                },
                content_available: true,
                priority: 'high',
            }

Also, I have made sure that extension is linked under the dependencies and Embedded App Extensions

Can anyone please guide me. Any help would be appreciated.