I tried some variations of the message but never got anything out but “None ist jetzt unknown”, what is want is something like “Florian ist jetzt home”.
For reference, you use trigger variables like other variables, they shouldn’t be put in quotes. When you put them in quotes they are rendered as a string so the stored value of the vriable isn’t available to your template.
If you were to use them in a template like you posted above it should be as follows:
Strange… trigger.name should render the friendly_name if one is assigned and fall back on the entity_id if one isn’t assigned. Another method is to get the friendly name is: {{ trigger.to_state.attributes.friendly_name }}.