In the REST API, is there a way to associate records for a multi-select lookup related list other than via the linking module?

There are two methods for the lookup:
1. via insert records API
2. via the linking module
...as described in https://help.zoho.com/portal/en/community/topic/kaizen-125-manipulating-multi-select-lookup-fields-mxn-using-zoho-crm-apis by @Subramanian K 

...but am not sure if the first works for the related lists - which is the newer many-to-many feature:

https://help.zoho.com/portal/en/kb/crm/customize-crm-account/customizing-modules/articles/linking-modules#How_to_create_a_many-to-many_relationship written by @Parvathi Nathan S 

Can someone clarify?