Main task timeline to reflect overall timeline and duration, summed up from subitems timeline

Description

Subitems are usually used to list down the list of tasks required to complete the main task. As such, the main task timeline and duration should be taking the overall timeline and duration from the first subitem start date to the last subitem end date. I’m aware that there is this subitem timeline column that sums this up. Instead of having an extra column, could we equate subitem time line to main task timeline and duration to simplify the table?

What are you trying to achieve

Main task timeline to sum up the overall timeline and duration from subitems timeline. Simplify the table and prevent the need to add one more column to show “subitems timeline” that currently sums it up.