Looking for advice on how to tackle legendary difficulty (TW:WH)

Now that I've completed the campaign for every faction on hard, I figured I'd finally give legendary a try (I always was pretty save-scummy so that was a concern), and boy is it kicking my ass. I've only tried the dwarfs and VC so far, and in both campaigns I feel like I've hit a wall and I have no idea how to remedy the situation.

Basically, because of the -8 public order penalty, expanding rapidly seems like it is out of the question, especially since the return on investment from developing poor provinces is pretty abysmal. Therefore I figured I would consolidate tight but powerful empires, to avoid overextending into contentious areas of the map. I stayed in Sylvania with VC, trying to get a necromancer economy going, and I stuck to the Silver Road and the 3 provinces north of it (Karak Ungor, Karak Kadrin and Mount Gunbad) for the dwarfs, since you're always exposed when expanding into the badlands.

The problem is, in both cases I could only ever maintain two-three armies, despite upgrading my economy as fast as I could. I believe I abused the raise dead ability correctly on VC to minimize upkeep, and I stuck to low-upkeep dwarf warriors + quarrelers, since they slaughter greenskins fullstacks anyway with their ridiculous commander and technology boni. Now, these stacks are pretty efficient; I'm winning every battle and they're enough of a deterrent to protect my frontier settlements. But the legendary AI really seems to hate human players, so that in both campaigns I've ended up with enemies on all side (basically, all the greenskins and VC are against me as the dwarfs, and all the humans and dwarfs are against me as VC). Meanwhile, the AI factions coexist rather peacefully with each other, meaning they can dedicate their full stacks to attacking me from all sides. Major factions like the Greenskins and VC can go up to 7-8 stacks, while even 2-province factions like Averland have around 30 troops.

It's gotten to the point where successfully ambushing and destroying 3 full enemy stacks through clever campaign maneuvering is a pyrrhic victory, since then my main army has to replenish its troops while the other AI stacks get to threaten my provinces (and given the precarious state of my economy and public order situation, any raiding or sacking is a serious blow).

So basically, I can't expand without over-extending, and I can barely defend. Meanwhile my enemies are getting bigger and better.

What am I doing wrong? Do you need more of a cheesy approach to the game to tackle legendary? Any advice would be greatly appreciated.

(As a sidenote, I'm using mods like tier-4 minor settlements and better AI build orders and unit compositions, which is probably making my life even harder)