Which kind of supernatural are you playing?

Vampire. I even have the mods for buildings and technologies that suggests you can download

Vampires are quite good at developing their capital specifically. Since you can move your capital around for free you can boost any holding that your char directly owns.
If it is that important to you then I would suggest the Praesenz power "perfect world". The subjects of your capital all work together to make it bigger and better.
Or you could learn mundane skills from the architect tree. Or you could go raiding and "find" new qualified workers in the cities of your neighbors.
First and foremost you should take care of the plague situation. Outbreaks just wreck your development. Boosting plague resistance ASAP is super important.

I see. So you can't just press the develop area button and it slowly ticks, that's good to know. And yeah I guess the architect tree would also be a good way to develop at least for your capital. Thanks for the advice!

No problem. The vamps main building in regional capitals also snowballs.
More development --> higher upgrades --> higher boost to development
One eco building wrecks development: Blood tax. Just don´t build it.
Don´t cry bloody tears when a certain midgame crisis happens...