I am searching for the easiest way to make use of Drupal as a front-end for a decoupled Drupal back-end.
The set-up I am trying to accomplish is:

• a Drupal 8/9 back-end as a central content material repository
• three Drupal 8/9 front-ends
• 2 non-Drupal front-ends

I wish to use Drupal as a front-end, as an alternative of some javascript consumer framework as a result of:

• I wish to transfer over current Drupal Eight websites to the central repository with out rebuilding them from the bottom up in a brand new framework.
• The event group is already accustomed to Drupal theming and twig templates
• I wish to have some native content material as properly

Background:
I am engaged on a set of internet sites that largely share the identical content material. Till now this content material was simply copy/pasted throughout, which could be very time-consuming for the positioning managers.

The largest website of those is an outdated Drupal 7, and we’re engaged on migrating it to Drupal 8/9. As an alternative of simply upgrading, I wish to centralize the content material. 2 different websites have already been in-built Drupal 8.

I’ve run a fast take a look at with exterior entities module (https://www.drupal.org/venture/external_entities), which I have been in a position to hook as much as JSON:API. These two are very awkward collectively although, and clearly not made to go collectively.

Is there a great way to perform this? Is there one other, higher manner of centralizing the content material?