Princess Leia and Kanan seem to be limited series, so maybe you should wait till they are over and pick the TPB. Star Wars and Darth Vader are both going to last for a long time. My favorite so far is Darth Vader, as it's dark and implements stuff from the Prequels into the dark times of the Empire, as well as offering very entertaining bad guys, with a sort of "dark" C3PO, there was also a "Dark" Chewbacca from what i remember, he was working with Boba Fett, though i don't remember what happened to him.
He main Star Wars title feels more like a direct sequel to Episode IV though, and in a way they are more cinematic, even the upcoming Kenobi story seems like something that could have been told on the big screen. If i had to recommend, i would advice you to try the main Star Wars title first, then if you want to read more, dwelve into Darth Vader.
Would be kickass to see Disney adapting some of these stories into animation to release on Netflix or another platform that would allow fans to enjoy these stories in animation.