Awesome Custom Fields for Jira Cloud

In my professional environment (construction), scheduling processes in calendar weeks is very common and has been proven in practice. Almost every construction project is carried out in calendar weeks rather than days. Would it be possible to implement this? In my opinion, this would be a unique selling point, as I don't know of any other app that offers this feature. Ideally, it would be configurable to display calendar weeks, but internally use dd/mm/yyyy with evaluation in JQL as calendar weeks. Thank you.

We would like to be able to have a "line item" field with an item description, quantity and cost field on one line. Currently I handle this separately with individual fields and it's a mess when working with more than one line item