It is not possible to select a starting point from another source, unfortunately. However, if you provide more information about what you are trying to achieve, there could be a workaround for it.
Mapping the order ID from Google Sheet to the watch module isn’t straightforward. Instead, consider utilizing the “get an order” module in WooCommerce.
For a clearer understanding, refer to the following Loom video link below. It should provide better clarification. If it helps, your appreciation would be greatly appreciated.