App dynamic shortcuts do not appear in assistant [when using an account different of the publishing one]

Question

I have an android app that:

• Does not use shortcuts.
• Does not use app-actions.
• Uses dynamic shortcuts.

The code to register the dynamic shortcut is like this:

            Intent intent = new Intent(this, MyActivity.class);
            intent.setAction(Intent.ACTION_VIEW);
            intent.putExtra("id", (long)id);

            ShortcutInfoCompat.Builder scBuilder = new ShortcutInfoCompat.Builder(this, "View " + doc.getName())
              .setShortLabel("View " + doc.getName())
              .setLongLabel("View " + doc.getName())
              .addCapabilityBinding("custom.actions.intent.ACTION")
              .setIntent(intent);

            if (!ShortcutManagerCompat.pushDynamicShortcut(this, scBuilder.build()))
            {
                Log.d("INTENT", "onCreate: Failed...");
            }

When I use it on a phone that has google assistant logged in on the same account that is used to publish the app, it works fine. As soon as I log out and use another account, dynamic shortcuts no longer appear in the assistant. This behaviour is the same with the already published app (as in app publicly available on PlayStore).

To me it furiously looks like some action must be performed to "get my app out of sandbox" so everyone can use the feature.

I'm aware that for apps using app-actions, you need approval from Google. However the app-action team at Google told me since I'm actually not using app-actions, it is not in their power.

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In my exchange with them app actions team at Google, I told them my app didn't use app-action or shortcuts, they told me the dynamic shortcut team confirmed it's ok to have just dynamic shortcuts, however it's in beta, and if I have issues I should post here. Hence me posting.