Backoffice Custom action Controllers (from plugins ?)

hello;
There is no clear documentation about creating custom controllers, I mean like in Synfony on any framework. It seems to miss !

How can we add action to de backoffice by means of a plugin ? Seems to be too free (i mean there is not real recommandation for this)

How can I achieve that ? I know I can plug on OnFormAction event but it not very satisfying in terms of performance ...

@sherpadawan, Have you seen the documentation on Admin Event Hooks?

Plugins for Admin are no different from plugins for front-end, they only subscribe to different events.

My question is more on how to write CRUD actions with a custom controller (which which ould inherit from a Grav CMS HTTP Controller).
It seems there is no recommandation for such a very common a baisc need.
Am I wrong ?
Listening event for action controller is not always a good practice, I just need to call a controller for a given url, and process the data...

The only thing I found is there
https://learn.getgrav.org/16/forms/forms/reference-form-actions

Any clue ?