Add a limit

This feels like it'd be more appropriate in another more general use module.

Have you tried https://www.drupal.org/project/entity_limit →

From my perspective this is a special requirement, not a common one. You could try to use the suggested module from #3, or you could also try using ECA → to achieve your custom needs.

Will close this as won't fix soon when not counter-arguments fly in.

The Paragraphs module has a limit for how many paragraphs a user is allowed to add to a node.

Let's say any registered users are allowed to create Storage Entities for a node. Any spammer can create thousands of these until the break the site.

If there is no limit, the use of storage entities should be restricted to trusted user only and this limits the usefulness of this module.

Relying on other modules (who might not always work as expected) to achieve basic functionality doesn't seem like a good idea.
In my opinion this should be built-in.

Where does Paragraphs provide that? Could you post a screenshot here to show where that setting can be found?

On the entity to which you add a specific paragraph (not in admin/structure/paragraphs_type)
Let's say on the node type Article you add a paragraph called Information

There are 2 tabs: Edit and Field settings
in Field settings

Type of item to reference:
Content

Allowed number of values:
Limited/Unlimited
You can add Limited: 3