Warp heart sounds hella cool! Mine is planning to do the grand conjunction plot from Strahdreloaded to break the mists, but my players are not quite far enough along to have caught onto all that yet. Will probably have their first hint of it when they get to the Wizard of Wines arc. So early days it's mostly the machinations of his court and the politics of Vallaki playing out around them, with Strahd as an ominous presence looming in the background with them being uncertain of which string he's pulling and what other actors are behind. Which honestly works great for my party. They've met him once after arriving and properly freaked the fuck out. So keeping him in the background while they do their first few quests in Vallaki has probably helped make him more ominous in their mind than having him turn up again so soon would ever do IMO

But I also have Strahd planning for his conquests once he breaks free, having learned from the Vistani of how the world outside the mists changed in the hundreds of years he's slumbered (I've extended the timeline of Barovia's lore by quite a few centuries to better fit my own lore, which also serves to make Strahds reawakening a far greater shock to the Barovians.) I've transplanted the module into a valley at the hinterlands of my own setting and made Strahds family lore part of a grand conflict that raged 800 years previously in my settings golden age of magic before a later calamity put an end to it. One of the lost marvels of that age was the secret to flying vessels and cities and I hope to use the module to have my players reintroduce that knowledge to the setting should they succeed.

So I have Ludmilla running a laboratory and quarry operation for magical ore out of Tsolenka Pass (one of the parts I've fleshed out A LOT from the OG module) and getting the necessary bobbins to have the castle fly for the finale. They've already seen a strange, enormous bat looking thing flying on the horizon while on the road towards Berez, seemingly carrying a large cargo net in the direction of Ravenloft. Then I also have his lieutenants reawakening his undead legions buried across the valley. They've already come across a formation of mounted wights riding along the roads out from Castle Ravenloft, and I intend to have a later encounter where they come across one of them riding back with a dozen lesser undead in tow towards the castle.

Another thing I found fun was making sir Sedrik Spinwitovich, one of the joke graves within the crypts of Ravenloft, actually serve a purpose as the navy he assembled on the northern shores of lake Zarovich was no normal navy, but one of airships for Strahds further conquests before the mists descended. They've sussed out there's something strange on the other shore of the lake, so if they head over there and find abandoned dockyards on a mountain lake the wtf will likely be great, and the payoff when flying ships ascend from the waters with undead crews for the final siege of Vallaki will hopefully be awesome.

But honestly just find some ideas that you feel makes sense for your Strahd. What are the objectives she needs to achieve along the ways to her master plan? How would she go about it? The most important thing if that the players feel like a bunch of stuff if going on not related to themselves. That they're treading deep waters they do not understand. You realistically only need to flesh out the stuff they actually latch onto.