Atlas is on the right track. The key thing here isn’t that you need to look up a video to get the full story, it’s that you have to look up a guide/video for EVERYTHING in Destiny. An update will add a quest saying “Find 4 feathers in this big open world map” and your options are 1) spend hours and hours combing every inch for well hidden collectibles, or 2) look up a guide from a full time content creator who worked with their community to find them.
For Destiny, the metagame is the real game. The game is not about shooting aliens and robots, it’s about optimizing which activities you should do in what order and when. If you aren’t willing to look up resources outside of the game, then Destiny is not for you. The community was very unhappy when Bungie streamlined leveling and gear in the beginning of Destiny 2 because you could feasibly run out of checklists at some point, so they added more RNG to loot and made you have to re-level more frequently because it adds more grind, because that’s what people want. My Destiny 1 guild mates that still play Destiny 2 have explicitly said this is why they like it so much now and why they didn’t like it nearly as much near the beginning of D2.
Also, even with this new shift to more frequent in-game story updates, most of the story/lore is still in item descriptions, side stuff, endgame content, etc. The raid for Beyond Light had a lot of important context and story beats in it, including for non-endgame stuff that came out the next week. And that’s what people like about it: there’s always new story/lore to learn about and discuss online, which keeps the community active. Compare this to Nioh and Nioh 2, which are also pretty popular loot-based action games but have almost no online community because those games have very good in game tooltips and straightforward story, so people don’t need to make or look up guides, so there’s nothing to talk about.