After some changes i figured, some cities are way too big and have to many residents.
Some cities reach too fast the one million due to the immigration and especially the basic ammenties infrastructure. To point out, in my games Paris had 1500 1 mio, and Kairo already 2mio inhabitants. Kairo started with amenties 7 in the game. So they had had an immigration growth in 1450 of 8k due to the rank of 7. They had a growth of half a million residents in about 50 years. Its not very historical to that time. Kairo had more than one million in the 1850s and Paris in the beginning of 1800. The Problem i see is that it causes issues with the Trade and Needs system. The Nile delta cannot support in the early game food production to trade to europe, because they eat everything by themself.
It would be good to reduce the amenties level in this cities. Why Kairo at 7 4-5 is ok too. Also i suggest to increase the cost or the possibbility to built it of amenities rank 7, so that this rank will be built only in the late game.