Can we enable the use of products inside an opportunity without configuring the Sales Catalog?

Summary:

Using the Sales Catalog would force the third party system to consume 4 webservices instead of just one, needlessly complicating the implementation of the integration. We would like to use products without Sales Catalog inside opportunities.

Content (required):

In Sales implementations on which CPQ is the product master, the products are created in CRM and are eligible in opportunities even though they are not included inside a Sales Catalog.

We are trying to achieve a similar functionality, but in this case, the product master is another third party system and we don't have CPQ.

We would like to simplify product integration so as to only have the third party system create the products through integration without perofming the lock, association with a product group and publish integrations, because that would require 4 times more effort and we are currently trying our best to optimize the times in our project.