Some people say that after you finish all possible maps you can reset all maps and replay them for full ap income again!
I don't know if that is true or not, but reaching 8000 will take a lot of time.
I have finished Far Land, next maps are giving this amount of APs:
Reconquest 1065 - 310
Fort Harbor - 314.6
Europe 1066 AD - 384.79
AD 1045: Roads of Silk and Iron - 474.37
Old Town - 517.08
Orbis Veteribus Notus - 545.2
Scandinavia and the Nordic Countries - 569.61
Asia: Population Density - 597.5
Africa - 613.74
Here is a screenshot of 3d phase advancements if you'd like to look at them https://i.gyazo.com/4abf438dab9b00e405a6503dbaf20fad.png
Edited 12/6/2020 21:57:54