I have actionable notifications with notify.notify service working so I’m not sure there - something sounds off.
I don’t think there’s issues with long timeouts, but realize that they won’t persist through restarts of Home Assistant, and depending on your automation settings you can control the number of instances. To disconnect the action from the running automation I often add the event as another trigger to the automation and then add logic to handle the normal trigger and the notification trigger separately. No wait needed in the automation then, just fire the notification and another instance of the automation handles the action.