Can I safely use the same UUID on independent sites? I'm trying to create a site building workflow which uses some sort of blueprint site, providing a shared, tested set of the Drupal core, modules, content types, paragraph types, a base theme, etc. for all our client work.

Projects/websites shall initially start with the same configuration as the blueprint site, but later on those projects are otherwise completely independent (different clients, different themes, modules will be added/removed, content types will change, ...)

From what I've read this should be possible with config export/import and by manipulating the UUID of the sites.

The question is: 
Is it a problem when ALL our projects share the same UUID? In the long run I'm going to end up with about 30-50 projects, each project will a dev and a prod environment, so in total there will be ~ 60-100 installations with the same UUID.

Updating the core and shared modules shall also be done and tested on the central blueprint site, and then pulled and merged by all projects.
This is a perfect use case for Features. You can export shared sets of functionality and configuration without worrying about UUID stripping or collision.


  The features module enables the capture and management of features in
  Drupal. A feature is a collection of Drupal entities which taken
  together satisfy a certain use-case.
  
  Features provides a UI and API for taking different site building
  components from modules with exportables and bundling them together in
  a single feature module. A feature module is like any other Drupal
  module except that it contains additional information in its info file
  so that configuration can be checked, updated, or reverted
  programmatically.
  
  Examples of features might be:
  
  
  A blog
  A pressroom
  An image gallery