Module development and code questions

In Drupal we can easily manage what fields of a node type are displayed or hidden and in what format (e.g. a text can be plain or html formatted, an image can be original or scaled) within the "manage display" tab.

Now with a headless website when I want to get all nodes of a specific content type, e.g. "GET jsonapi/node/cat" Drupal will return ALL fields with missing formating. But how can I request one of the many view modes that I have defined?

At the moment I am entering information twice once in content type A and again in content Type B.

The fields are the same as I reused them, but are there any clone modules out there that will work with Drupal 10.1.4?

I have searched and none seem to be available for Drupal 10.

The cloned content would be text fields and date content.

Cheers

I have created a content type name "Customer Distribution" to take the population of male and female from different locations.
The fields in this page are:
location
male population
female population
remarks

I have a basic view set up to show a result list of an "articles" content type (listing the title linked). There are three terms in a taxonomy for three newsletters and are all tagged under one of the three, and filtered as such. The ask is to add a solr search for this content type and add a fulltext search to it.

As I'm trying to do this I found that if the view is using Content I can't add Search: Fulltext search (not available) since I would need to create the view with an Index Article index. This allows the fulltext search but I'm finding it difficult to add the filtering.

I have the following construct in one of my projects:

  $message['body'][] = Markup::create('<br />&nbsp;<br />' . t('This is an automatic e-mail from @sitename. To stop receiving these emails, change your notification preferences at @host/user/@useruid/notify.' . '</p>',
     ['@sitename' => $sitename, '@host' => $host, '@useruid' => $useruid], ['langcode' => $upl]));

GitLab CI testing is not happy, and tells me:

I have built a field formatter this way: