Allow to control the 'SendNotification' background transparency

As a Roblox developer, it is currently impossible to change the StarterGui:SetCore SendNotification background transparency.
In the example below, the text of the notification is almost unreadable as it is over a previous Gui:

If Roblox is able to address this issue, it would improve my development experience because being able to modify the transparency of the SendNotification background, the text will be more visible.