When casting a lovelace dashboard - for example to a Google Nest Hub - the locale/regional settings of the casted lovelace dashboard seems to default to US and I have not found a way to specify the locale/regional settings for the casted content.
cast_home_assistant_to_nest_hub:
alias: Cast Home Assistant to Nest Hub
sequence:
- service: cast.show_lovelace_view
data:
dashboard_path: lovelace-hub
view_path: home
entity_id: media_player.nesthubxxxx