In the early days of Drupal 8 we used the EntityTypeManager to render some plugin blocks or other entities. But this changed a bit, EntityTypeManager got deprecated. Here's a snippet on how to render a block inside your twig files. In my mytheme.theme file I use the following:
/**
* Implements hook_preprocess_node().
*/
function mytheme_preprocess_node(&$variables) {
// Display the breadcrumb nicely in the node
$block = \Drupal\block\Entity\Block::load('mywebsite_breadcrumbs')->getPlugin()->build();
$variables['breadcrumbs'] = $block;
}
Now, inside my node--article--full.html.twig I can use:
{{ breadcrumbs }}