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You have a node type. You want to serve that node type in blocks only. So, you need to disallow the node view page. To do that, you need to create an event subscriber, redirecting you to another page when the condition is met (Front Page in our case).
Sometimes, you need to add a field to an entity programmatically. Entity storage will automatically process the storage in most cases. This technique is especially good with computed fields.
Nodes are entities in Drupal 8. So, you no longer load a single node, but rather, you use the entity interface.