Clarification for sales only

Based on your description I draw the following map:

My approach would be something like this:

I would use different processes for products and services because there are big differences, in timing, in specifications, in participants, in needs;

I would use the Design & development process in support of professional services sales. I that case the offer is designed case by case following customer needs and requirements. Perhaps this article could be helpful - Case study: Design and development in the software industry - https://advisera.com/9001academy/blog/2017/02/08/case-study-design-and-development-in-the-software-industry/

I will also add this template: - Procedure for Design and Development https://advisera.com/9001academy/documentation/procedure-design-development/