Sylvanas's ultimate goal

I have been thinking about Sylvanas's actions in BfA, and her involvment in the Wrathgate events. Since Afrasiabi said that she was somehow involved in the disaster of Angrathar, lots of theories came with it, but I think it is a proof that Sylvanas was ready to do ANYTHING to defeat her long time ennemy : Arthas. She's now acting the same in BfA, which means she has a new goal, but which ? Obviously it's not about the future of the Horde. We all know that after Arthas's death, she committed suicide, and made a deal with the Val'kyrs in order to come back because of the endless suffering death was for her. From that time she was seeking for ways to reach immortality, for her and her people. In Legion, she nearly did it by making a deal with Helya, an entity related to death, but Greymane ruined it. But did he ? What if the lantern she has been given was only a taste of the power Sylvanas could get if she helped Helya ? Now, let's talk about the deal : I think Helya asked Sylvanas to kill the other death-related entity that's around Azeroth : Bwonsamdi. Knowing how much of a strategist Sylvanas is, and with her position as a warchief, she planned everything to try to create a clash with the Alliance, starting from Silithus, the burning of Teldrassil, the battle for Lordaeron, etc.. knowing it'll end up with a total war between factions, and a need for both camps to make allies. So, the Horde is desperately looking for new allies, so, Sylvanas decides to reach out to the Zandalari, who are close to Bwonsamdi, in order to get the chance to kill him somehow. That's why Bwonsamdi doesn't like her and asks Talanji for her head in the Zandalari recruitement scenario. He feels threatened, and needs Talanji. But Talanji is now bound to the Horde, and Sylvanas must feel somehow superior to her because she knows that she'll free Talanji of she kills Bwonsamdi herself. How will she do it ? By using Xal'atath ? Asking the Blood Trolls, whose magic has proven useful for killing loas ? Who knows ? Now, the deal with Helya. I think that, with Bwonsamdi's death, Helya would have total power over death and souls, and maybe give a bit of it to Sylvanas, and MAYBE give her Bwonsamdi's role, as her personal minion. With those powers, Sylvanas would have control over death, and therefore save her people and herself. What do you guys think ?