Push Notifications Background Handler

At the moment I am using Firebase and Capacitor APIs for Push and Local Notifications.
After reading into the subject of notifications and the differences between Data & Display notifications I am at a roadblock.

What I would like to achieve is to send a data notification from a Cloud Function on Firebase that is then presented to the user when the app is in the background (dead or inactive), a key feature being that a user can reply inline with this notification - like you can do on any chat application.

I can partially achieve this by sending data notifications, listening for them with with Push Notification API

PushNotifications.addListener('pushNotificationReceived' => (notification: PushNotification) => {})

And then displaying them with the local notification API.

async showNativeNotification(data: any) {

        if ((await App.getState()).isActive) {
            console.log('Application Open - Notification Suppressed', data);

        let notifTitle = 'Knapsack';
        const prefColour = await this.prefService.getPreferences();
        if (data.location) {
            notifTitle = `${data.location.topic.name} - ${data.location.workspace.name}`;

            notifications: [{
                id: 1,
                title: notifTitle,
                body: `${data.sender ? `${data.sender.name}: ` : ''}${data.message.snippet}`,
                attachments: null,
                iconColor: prefColour.userPrefs.theme ? UtilityHelper.themePropToHex(prefColour.userPrefs.theme.properties.primary) : '#f74258',
                actionTypeId: 'chat_message',
                extra: data


Actions Being Registered Earlier in the App:

                types: [
                        id: 'chat_message',
                        actions: [
                                id: 'mute',
                                title: 'Mute',
                                destructive: true,
                                foreground: true
                                id: 'reply',
                                title: 'Reply',
                                input: true,
                                destructive: true,
                                foreground: false,
                                inputPlaceholder: 'Ab',
                                inputButtonTitle: 'Send'

This produces the exact thing I would like when the app is in the background somewhere.
However the issue is as it’s a data notification this function never fires when the app is completely killed.

If i send a display notification however then this comes through fine when the app is inactive & when the app has been killed, however to my knowledge there is no way of allowing input onto these, and registering events. Am I missing something or is this purley something that doesn’t exist at the moment?

I can make to with the boring un-interactive notifications but would love more flexibility. Any information or help on this topic would be much appreciated.

I’ve spent countless hours trying to get this to work and from all I’ve researched, it appears that data notifications currently don’t function in the background. Hopefully this is either not the case or it gets fixed soon!