I conquered an Independent People city early on, then it became my city. The problem is I don't want it to be a city, I want to integrate the territory to my other bigger city. From here, usually the solutions are:

1. Merge the city later. I wanted to do that, but when I had the tech, the cost of merging city skyrocketted. Don't say I lack influence, on game-end replay I had the highest influence production and it still can't keep up with the cost of merging that city/cities. Yes I expanded quick, but the cost is ridiculously high. I was finally able to do that 2 eras later on about 25k influence cost, just to merge one city containing one territory mentioned above. As comparison, creating new outpost in these turns cost about 200 influence, attaching outpost costs about 700 influence.
2. Wait until the Independent People decline, then I can create outpost there. Here, the risk is that they are assimilated by others first. And in my opinion this is a very lame path.
3. Merge the city using money. I tried to do that, but the cost is about twice the influence. So when it needs 25k influence, it will need 50k money to merge and a civic to be picked first.

1. How is the merging cost calculated? I see that adding and destroy (ransack) district in corresponding city make the cost fluctuate, but it still shouldn't be ridiculously high. Do total districts across empire count?
2. Will Independent People gameplay be improved? It can't be just like that. They can't exist just to come and go and be conquered or waited to be perished. Civ6 or Endless Legend have better gameplay with this.
3. Please add an option to downgrade a city to an outpost. Whether it's after conquered or permanently available.

Merging cost is strongly tied to the difference in infrastructure between the two cities, if the cities have identical infrastructures, the cost is low, else it can get really high. You can ransack the city center of any city to destroy the city, after which you can build an outpost and attach it to one of your cities.

Goodluck wrote:

Merging cost is strongly tied to the difference in infrastructure between the two cities, if the cities have identical infrastructures, the cost is low, else it can get really high. You can ransack the city center of any city to destroy the city, after which you can build an outpost and attach it to one of your cities.

I guess it is an exploit but you would lose all your pop in that city so not sure it's really worth it.

Right now with colony plans you could make cities that start with several districts after which you can merge them together to create a single megacity that have 100+ districts, all this for maybe 10k influence.