Idea for a QoL feature "Encounter Codex".

[Jargal]

Not really. Most of them say much the same thing and most people usually come up with the same strategy (or few strategies) anyway.

One of the things that are annoying when revisting content is just to look for inevitable obnoxious ways of finding very simple information that not always needs a 20min guide on youtube nor the need of having various links for stuff?

Check the battle log. Status effects are shown in there and can be linked like items and PFs can. You can also just get to the mechanic and hover over it.

The battle log is i'm sorry, very crappy (just like almost every UI in this game terrible to navigate), just put this information in a straight to the point menu.

The type of damage dealt by the attack is stated in the battle log and also as fly text.

Temporary recorded and not always up for the player to check in the future unless he goes in the fight again (assuming the player took a very long break since stepping on the content, also like I said, the battle log is terrible and awful to navigate to find simple information in a fast maner.

This is true. Recording and then reviewing footage is the most effective way to work out complicated mechanics when doing it blind and that's exactly what these "other sources of information" have done for you and is why most people check these "other sources of information". Even in the first hour of a raid release, people are watching live streams on their second monitors so they see if other people figured it out before them to save time.

That is not very user friendly, I'm not critising the existence of guides and information outside, but not everything needs to be seeked out of the game, there's information and information, not everything needs to be checked via recordings, or screenshots or on a second monitor, that's the opposite of being something simple and straight to the point. Guides will still exist, I'm not asking for a step-by-step guide in-game, just a way to avoid having to do hops like I'm doing a college research just for most of the times check a very simple thing.

Like the Battle log which does exactly that?

Battle log is shit like 90% of this game's UI, sometimes certain types of information can just be optimized visually to avoid wasting time scrolling on a terrible chat window, also the battle log wipes that information if you get DCd or you know, log off at somepoint after a day of prog.