I think having something like this is spot on for the vibe of the game. If it was incoperated to be your characters storybook or timeline in the final game it would be very cool. I very much enjoy the idea of needing to "find" specific items in raids that would then allow you to get more information about the story. Having these things be more secretive makes it all the more special to go and discover it.
Its a fantastic idea to get something like a more detailed factory map after gathering all factory Intel. As an example something useful like that should be achievable in game not from something like a code in a video. I think the code idea is best for stuff like general tarkov news and lore attached to content releases, etc. Then only those who see the video might know what happened in tarkov.
This is a cool way to make finding lore a seperate part of the game while incorporating it into other things then just the game world.