Is it possible to have a flashing icon when a mail arrives in Outlook?

The Notifications of my Outlook applications for the arrival of a new mail are as follows:

Setttings, General, Notifications

As you see, it mentions the possibility to show an envelope badge in the taskbar.

That’s good, but not enough: it happens regularly that mails arrive and I only see them far too late. Therefore I’d like a “flashing” icon on my taskbar. I can create this myself (using a GIF-file), and replace the current envelope image with my newly created GIF-file.

Where is that envelope image file stored on my computer, so that I can replace it by my GIF-file?

This is the content of the “About box” of my Outlook application:

Microsoft Outlook Version: 1.2025.1027.200
Client Version: 20251024006.24
WebView2 Version: 142.0.3595.53 (Stable)
Session ID: b1b95ef5-9ffc-3b4e-bedc-63d109b90623