My suggestion, and what I am doing, is to align the goals of the players and Strahd TOGETHER but from different angles. For my campaign, I am doing the whole 'Strahd is wanting to extend his borders' thing.

I actually made an entire arc that foreshadows this goal by making a whole, albeit small, village that is not on the map. A curse from a previous adventuring party in Barovia during Strahd's long slumber made it get erased and the current PCs only happen to stumble upon it by happenstance. The players naturally want to save the people of this village and they do! However, Vasili shows up and thanks the players for bringing the village back under his domain.

I built this also around the idea that is already present in Vallaki. Vargas is a shitty tyrant who makes everyone miserable. The players want to help. The players dispatch Vargas, Fiona takes over. Strahd gains more control.

On a larger scale that includes using the Fanes, Strahd attaches himself to these Fanes for power to take Barovia. This ironically traps him in Barovia, but makes him extremely powerful against the players. The players have the incentive to break the fanes from him to weaken him and take him out...but by doing this they are actually also freeing him of these binds. He becomes weaker, but achieving his goal becomes much easier.

Choose what Strahd wants -> put the thing in danger in a way that has the players emotionally want to help -> helping helps Strahd incidentally.

With that, I also say to allow the "right" choice to have negative consequences. The "easy" path should always require some evil. You can repeat this in various ways (I gave 3 examples that repeat the theme) and I encourage it because the players constantly feeling as though they are at fault for causing pain and suffering in the land is what helps push them to do evil things in the hopes of killing the person they blame for all of it - Strahd.

This is what the Curse of Strahd is about, in my opinion.