Ability to apply updated field templates to an existing record

I'm a product manager and I've created many initiatives using my company's pre-defined custom template. The template included the initial estimate field and it has been measured in time. Our company changed the measure from time to story points, but the note below that setting states "This default value will be used when new records are created. Changing the default value will not affect existing initiatives, releases, or features." So now the task ahead of me is to convert all my initial estimates from days to story points. I submitted a ticket to find out how to do this after trying myself, and was told that the only way I can convert this field to be measured in story points instead of days is to copy the initiative and then enter the estimate in. That works well and good, except copied initiatives will lose the entire history of when information was changed, which is super valuable context to have when we're trying to figure out when a decision was made and by whom, as well as the comment history gets lost. This is a big problem, because some initiatives have lots of comments from colleagues reporting on behalf of customers or anecdotal data and manually copying and pasting those over is burdensome. It would be great if you could please provide an option on the initiative to refresh or update the template to account for changes in that template so I can conform to my company standards while not incurring excessive work to prevent the loss of information.