Magento file structure and documentation.

I am now getting into magento module development and it’s amazing how little info exists online structured well and how available it is.

I want to create a payment gateway module and I am starting from the basics. Here is a post from the official docs. The dude in the videos, goes into how you do things and doesn’t even bother to explain the terminology.

Coming from WooCommerce, wtf is a Module, wtf is a plugin? When do you use each. Looking online discussions, makes it even more confusing because everyone has their own definition.

What’s the equal to woocommerce hooks? Some call it function calls tapping or interceptors.

In the end, where is the documentation for 2.4.4(and above that we have to support?). What is the file structure of a module supposed to be and more importantly, where is the actual documentation of the XML files?

For example, I see module.xml, system.xml, di.xml, events.xml and 50 other XMLs. Where do I find their documentation for accepted values and an explanation of what is each xml file for? When to use what?

Adobe devdocs documentation is utterly lacking. I would appreciate any pointers to get out of this swamp. No other ecommerce platform I’ve worked with has such bad documentation.