Create block content programmatically
If you want to create content for the custom block type basic:

use Drupal\block_content\Entity\BlockContent;

$block = BlockContent::create([
  'info' =&gt; 'block 1',
  'type' =&gt; 'basic',
  'langcode' =&gt; 'en',
]);
$block-&gt;save();


And add a french translation:

$french_block = $block-&gt;addTranslation('fr', ['info' =&gt; 'bloc 1']);
$french_block-&gt;save();


Custom block types are content, not configuration. See this answer https://drupal.stackexchange.com/a/218244/47547