Canon in Star Wars is, to paraphrase Yoda, always in motion. What used to be considered purely canonical were the theatrically released movies only. Not even the novelizations of said movies were canon, as they were based on early drafts of the screenplays. Then the tiers of canonicity went from there to the novels that were written in between the original trilogy and the prequels getting released, then down to the comics and video games and sundry stuff like cartoons, toys, and the RPG game. When we were living in the time of no expectation of any future movie content, those were only considered semi-canonical for fan’s purposes of discussion and argument. They were all iffy, contradictory, and sometimes downright nonsense, but each had a few elements that seemed worthy of discussion, and they all were establishing a timeline of events that were consistent, up to a point.
Then George released the Prequels, and whole swathes of the novels and comics were instantly obsolete as they overwrote certain character histories, firmly explained historic events, and introduced concepts that hadn’t even been considered.
Then Disney bought Star Wars and the rest of the novels and comics were deemed obsolete, now termed Star Wars Legends.
Now, with these TV series, the ability to establish new canon is in the hands of other creators, and the stories are unfolding in a similar way the Legends novels and comics used to do; smaller stories about characters, rather than large galactic events. But they are plucking characters and plots from those Legends stories as well. Things like the Dark Troopers, Grand Admiral Thrawn, or the Dark Saber are all drawn from questionably canonical sources of the past, now re-established as definite canon now.
So, @mordecaiB, that you are lost by all of this is not only forgiveable, it’s kind of expected. It’s a jumble, and is unlikely to make sense to most people for a long while yet. The nerds are here to answer your questions, and no judgement will be passed if you’re confused by any of it. My advice is not to get too worked up, and just enjoy the ride.