Seamless data carry over from an item to its subitems

I am looking for a way in which item’s values of all or selected columns will carry over to its sub-items in a seamless way without having the user take any action.
For example, if an item is associated with a specific project name, I would expect that any sub-item will be associated to its item’s project.
Another example: Item represent a block of activities having a needed end date. In this case, user will be able to add sub-items that will reflect the needed end date along side with another date column that will indicate the expected end date of the sub-item allowing comparison between column and sub-item entries.

On same note, perhaps having an automation that will populate the needed data (if needed) from the item level to the sub-item level can support this suggestion (at the moment subitem automation is extremely basic and does not allow any flexibility around it).