The whole sounds great! And it looks great! Despite some problems, which I will list below, you have done an amazing job!
I really like the unchanging nature of the city landscape, that the buildings are not being replaced by every now and then - it's really nice.
After several tests, I noticed some not very favorable features or mistakes.
All towns look very similar when you start the game. Even in Cities there are no larger or characteristic buildings.
Earlier, the city center was almost the entire city - the suburbs hardly existed. Here, the center with large buildings remains small in the case of city development, and thus becomes disproportionate.
In the current version, the entire suburbs look the same. The development of infrastructure where inhabitants are transported is a very good solution, but with this arrangement, player doesn't deal strictly with transport services while building his lines, but the expansion of the city. He doesn't have to plan the line, adapt, just where he builds it, there will be more profitable houses. If there were some diversity it would be more interesting.
In arctic climates, larger buildings are placed in snowy areas than in those without snow. Other buildings seem to have been assigned to both areas or a different layout.
Also in the Arctic climate, in the suburbs, when the city is already large, "Shop and offices" buildings are being built everywhere
With the addition of OpenGFX + Landscape in "alpine" mode, buildings don't adapt their appearance - the height is taken into account, not the type of ground.
Acceptance of "all" loads by buildings is not always a good option. Sometimes, scenario assumptions using a script can be such that not every city should have a chance to develop fully. Then the lack of supply of some loads stops excessive development. The solution here would be an optional exclusion of acceptance of certain loads, including even goods and food. Then the possibility of supply would be determined by the presence of shops or other enterprises in the city. On the other hand, if they accept, they could also accept building materials. These, in turn, could have some impact on the development of the area, perhaps even greater than passenger transport.
The possibility of selling alcohol at stadiums is a quite controversial idea.
It doesn't matter for me and probably most people, but there are people who become very aggressive after drinking and therefore it is banned in most countries.
In temperate climates there are no markets in the suburbs.
I would have several suggestions for points 1,2 and 3. I don't know if they are definitely possible, but maybe they will be somehow useful. I will try to post them tomorrow.