Artificial happiness

In my quest to make the AI in Civ 6 better I have hit a snag.  Much of my efforts thus far have been focused on making terrible decisions into reasonable ones so that the AI won't be so outclassed, but I have run into a structural problem I don't quite know how to solve.  The AI simply does not recognize and attempt to solve happiness problems.

Nearly every civilization I have conquered in my past couple of games has had huge problems with rebels spawning around its cities and mulching its army as well as pillaging its tiles.  This only happens when you don't pay enough attention to happiness and find ways to get amenities to make your people happy.  The AI does try to purchase luxuries from me, but eventually they get mad at me for some reason and then refuse to trade, even when they desperately need what I have to offer.  They also flat out don't build Entertainment Complexes, which are a necessity for keeping a large empire functional.

In my last game I witnessed 4 of 5 AIs having huge happiness problems to the extent that they were swamped with rebel units.  When I finally conquered the entire world I checked and discovered that not a single AI had ever built a single Entertainment Complex.  They just sat there with terrible happiness problems and ignored it, and that ruined their empires.  After I took their cities I built many Entertainment Complexes in the conquered territories to support my expansion - it is not difficult to do, but they ignored it completely.

This undoes me in several ways.  One, I can't do much to make the AI better if it insists on being an idiot like this.  I know for sure I can't fix its terrible combat planning, but I had thought at least I could make economics work better.  I also tried some changes out where I reduced the bonus Amenities in each city from 1 to 0 in order to tone back Infinite City Spam strategies (I buffed Entertainment Complexes to 2 base Amenities to compensate, and promote more developed cities) but that just made things worse for the hapless AI.

I don't need much to work with.  I just need an AI that chooses to build the district that makes happiness when it has happiness deficits.  I can fix the rest with simple numerical changes!  But right now I don't even have that.

I really want to fix this.  I hate that the way the AI is buffed at higher difficulty levels basically makes the early game absurd in the favour of the AI, and then it plays so badly that you are nearly guaranteed a win in the late game if you manage to get there.  I want the early game to be much more fair so the player can actually get a religion or build a wonder if they really want, but have the AI present some kind of reasonable challenge later on.  Right now I am kind of lost in how to promote that.