How to make work order without BOM?

At my company, one of our product lines is fully customized for customers. Currently, the process to make one entry is very long, as each product needs its own BOM, and we only make one of each, with different serial number

The current process is as follows:
Create the product. Include UOMs and serial number. (This product is made once and never used again) (eg Custom Product xx1093, 10F, 5Ohm)
Create a BOM just for this one product. (This BOM is never used again)
Create work order for this one product.

I want to improve it by directly inputting the work order, but work order requires BOM. From my perspective, there are 2 ways to continue, but both are very idiosyncratic:

  1. Create a custom doctype which will be similar to work order, which automatically adds the Manufacture STock Entry.
  2. Write an external script to process our company’s internal manufacturing logs (calculate everything automatically) and import into Inventory List and Work Order List.

Is there a better alternative?