With an update, it is now at least possible to use the notification tag. Since the notification actions unfortunately still do not work, I send the link to which the Progressive Web App should direct via the notification tag. In the ServiceProvider I then use the tag to open the correct page. Works so far wonderfully. However, I am eagerly waiting for the actions to work. I hope this can help you a little further.
PhilippBrosig
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Unfortunately, Sound, Icon and Badge do not work for me yet either.