Is your feature request related to a problem? Please describe.

Since version 5.2, @joomla offers to create custom styles for links in the TinyMCE settings, but there is nothing similar for embedded content.

Describe the solution you'd like

I suggest adding the ability to create your own custom shortcodes in the TinyMCE settings.
I don't see the need to load third-party components with third-party libraries and scripts for such a basic feature.

Additional context

Out of the box shortcodes will be a great solution, replacing all possible third-party components for embedded content.
Websites on Joomla should be as fast as possible, and third-party developers like to add their huge third-party libraries and scripts for such a basic feature, which makes the website load much longer than it should.

Each administrator would be able to create their own set of shortcodes, instead of loading huge libraries of shortcodes from third-party developers on every page of their website.