Add other costs line items on invoices

I produce custom furniture from manufacturers and various designer showrooms. I would like help to see addl. line items/selections/options, for example, this order I am quoting right now:

1) Cost of upholstered coffee table - this is done already by DF but…

2) Plus the cost of COM fabric from another vendor (v.s. me having to calculate on another program i.e. excel/google sheets/my calculator)

3) Plus the 10% discount on the backend from the vendor for ordering in August.

4) A separate column (backend) for quoted shipping costs from the vendor to my receiver (I dont want the client to see that I am charging backend shipping and front end)

5) Add a line for something like a tariff tax/freight surcharges.

I want this all wrapped up in the costs of the goods. All these years I have been manually calculating this on google sheets and its a nightmare trying to capture all of the moving parts for my bookkeeping (not to mention so much room for human error) and then not wanting to show the client on the front end that they are paying for said (tariff tax, backend shipping, COM fabric costs). I only want them to see what their total costs is plus shipping white glove to client.

Since I do ALL my invoicing through DF, I really need help making this request possible.