Best way to set up multi-year project template

I am helping a colleague convert a excel file used to manage multi-year develop projects. They currently work in a T-9 year to completion based upon a 9 year expected program. They start a new spreadsheet each time a project is launched.

They currently work in a target launch date minus X years with milestones at a to be achieved in certain quarters across the 9 year window.

Example of excel spreadsheet columns below, see T-9yr, T-8yr, etc…

I am thinking that in Smartsheet, it would be a case of detailing the program milestones and then setting each milestone as a dependency on the previous one. I would then have a row where detail the project start day and I should then get a 9 year road map timed off of my project start day.

I just wanted to ask if I am thinking about this is the right way or if there are other options/experience that could be helpful.

Grateful for any thoughts