Organizing the souls at my disposal would be the first step. I’d exchange future perks to any ghoul(s) that could bring the masses to toe the line. I wouldn’t be bothered with micromanaging and could be freed up to pursue the bigger issues.

I’d convene with a single mortal to act as my emissary in the mortal realm (to limit costs) and send them to nearby hamlets/villages. I’d authorize them to offer percentage stakes in large scale plantations/factories manned by the spirits at my disposal. The only cost? The land needed and the bodies of their deceased. Most piss poor farmers would be eager to take the deal, I’d assume.

From there business can grow organically. Money buys all in the mortal realm, including devotion. And devotion in the mortal realm buys power in almost all other planes.