I'm going to preface all the following commentary by repeating my earlier statement that this is not the map to try moving up a difficulty level on.
So here's a look at your capital:
Pyramids, well that's good. But you are stagnant at 5 below the happy cap and forcing two specialists. That's...not as good. As I noted earlier, this is a very, very low food capital, which limits what you can do in the first place. But at least grow it to the happy cap!
I mention the Pyramids to point out this:
....why did you switch to Universal Suffrage? If you were playing Fredrick, I'd think you had AI autoplay enabled, because I can't for the life of me understand this. US boosts only towns, of which you have none. The reason people build the Pyramids is to switch to Representation early.
This is easily your city with the best terrain:
But it's building wealth without any improvements! There also aren't any buildings. You've switched to CS to run scientists everywhere (which can make sense with Rep), but it's more important to whip infrastructure first in cities like this (very high food, very low hammers). I checked your units - you have 6 workers, which is exactly 1.5 per city, but what have they been doing? Your empire is full of unimproved tiles. Two workers are also sitting right next to Kublai's border...?
Finally, this city should be moved one tile SE to pick up the corn that is not in the shot:
Also, you are again stagnating the city to work a scientist when you could be working both gems instead. This city obviously isn't going to farm great people (especially without the corn). As a general rule, do not found any cities without at least one food resource (or at least some floodplains). This city will never do much of anything.
I didn't take any more screenshots, but you also have an army consisting almost entirely of archers (i.e. passive defense). A few spears would help to repel Kublai's mounted units. On the other hand, none of your cities are producing any units in the first place.
Honestly, I'd suggest trying another map with more green tiles and going with an economy that generates beakers through cottage-commerce. It's easier to "set and forget" cottages while you work on some other aspects of the game.