Even native speakers will have difficulty understanding a conversation full of unfamiliar slang, or spoken in an unfamiliar accent. For that matter, even standard terminology varies in different parts of the world, and within a single country. This is true of any natural language, and there is nothing anyone can do about that.
Listening to people with a particular accent will help you recognize the sound patterns and map them to more standard pronunciations. You may need to pause and replay the recording many times, or watch it with others who might be able to make out distinct sounds.
Quite often, however, you can pick up sufficient meaning from context to get through it. Science fiction and fantasy works, for example, create their universes in part by throwing out unexplained terminology or references that may initially have no meaning at all. It was not until some time after I started watching shows like The Wire (set in Baltimore, USA) or Letterkenny (rural Ontario, Canada) that I bothered to look up cold patch truck or #lamplife, and I found that the knowledge did not especially deepen my appreciation.
So too in this video, context provides clues that something that is gangsta is praiseworthy among this group, and something that is o.g. even more so. You might also pick up that o.g. carries a sense that something or someone is worthy of respect as a veteran or old-timer, because the newcomer is of an older generation, and keeps referencing older and older experiences (using a rotary phone, traveling by horse, using black powder musket, etc.).
The rest of it is not especially relevant. From context, it's clear ése, cabrón, and homie are terms of endearment—with a different demographic, it might have been bro, dude, and buddy. Similarly, the facial expressions and body language explain the distance between respeto siempre and ¡callaté! and to wish a pox on anything is a disparagement, not just your crica. The reference to tagging is similarly incidental and could have been to any activity.