In the interest of variety and adding more types of venues, I humbly suggest adding a pair of football like stadiums to South City, one with dirt field, the other with asphalt, with access in and out via tunnel. Similar stadiums have been used as part of rally stages and rallycross courses at the X games, as well as Race of Champions. They would make excellent autocross layout spaces, for more compact asphalt races, similar to the autox races of old, as well as providing something that hasn't really existed in the game yet: A dirt autocross field. Additionally, the large parking lots surrounding arenas and sports venues often host autocross events.

https://youtu.be/-NG4o7mAYXU opportunity to add dirt elements to autox
https://youtu.be/5FYTEkjMSBw off road stadium racing could be a blast with the RB4 or other rally cross
https://www.autosport.com/other/news/141113/things-we-learned-from-the-2019-roc ROC, Autocross and some asphalt rally x style sprints on a course as tight as one of the kart tracks could be utterly thrilling

Quote from KeiichiRX7 :

In the interest of variety and adding more types of venues, I humbly suggest adding a pair of football like stadiums to South City, one with dirt field, the other with asphalt, with access in and out via tunnel. Similar stadiums have been used as part of rally stages and rallycross courses at the X games, as well as Race of Champions. They would make excellent autocross layout spaces, for more compact asphalt races, similar to the autox races of old, as well as providing something that hasn't really existed in the game yet: A dirt autocross field. Additionally, the large parking lots surrounding arenas and sports venues often host autocross events.

https://youtu.be/-NG4o7mAYXU opportunity to add dirt elements to autox
https://youtu.be/5FYTEkjMSBw off road stadium racing could be a blast with the RB4 or other rally cross
https://www.autosport.com/other/news/141113/things-we-learned-from-the-2019-roc ROC, Autocross and some asphalt rally x style sprints on a course as tight as one of the kart tracks could be utterly thrilling

I'm liking the idea. However I think some kind of height map editor is needed to get the banks and jumps you see in the video.