Consider this article for challenges with the Vendor Bill Payment PDF

https://blog.prolecto.com/2021/03/20/revise-netsuites-vendor-bill-payment-advanced-pdf/

At this time, I don’t believe there is any method to delete or remove the “Other Relationship” once it is intact.  I summarized the peculiarities of using this feature in this article:

https://blog.prolecto.com/2020/09/12/netsuites-entity-other-relationship-idiosyncrasies/

I recommend reviewing this article posted which helps people learn the best practice for working with Landed Cost:

https://blog.prolecto.com/2016/05/22/offer-superior-netsuite-landed-cost-practice-with-late-vendor-bills/

Have you reviewed my article that contains the SS2.0 button code pattern?

http://blog.prolecto.com/2017/06/10/add-form-button-to-call-netsuite-suitelet/