Managing a world wide master rollout based on regional multi-market, multi-language portals in Drupal 9

For a leading food company with world-wide operations we are currently rolling-out a world-wide master code basis to be used for their B2B section. They expect a flexible basis configuration that can be used in a variety of different markets (organized in regional portals) that act nearly completely independent from each other and are only loosely aligned.
Managing the different expectations and requirements was a huge challenge that needed to be carefully planned. We present our learnings here with a focus on content, processes and design challenges.
* Creating a flexible component system based on Drupal paragraphs that fits everyone
* Aligning market requirements from all over the world
* Creating a role and permission model for different editorial workflows in multi-market, multi-language portals
* Design considerations for RTL, accessibility, international design elements and flexible font sizes