The only known source of problems with missing icon or errors upon loading the is when you have ever used/subscribed Gooee mod before and it's no longer subscribed. When Gooee was subscribed and enabled it copied some filed to local mods directory but they will brick other mods once the Gooee is later unsubscribed.
[Edit, something has cut half of the original message]
You have to go to C:\Users\<your_username>\LocalLow\Colossal Order\Cities Skylines II
(hint: hit Ctrl+R and paste this %localappdata%\..\LocalLow\Colossal Order\Cities Skylines II
into "Open" input field then hit Enter to open the directory automatically)
then find and delete folder Gooee from the ModsData folder if exists. That should solve the problem with missing UI button. If loading error is still present you need to share Player.log and Traffic.Mod.log (in Logs folder), otherwise I won't be able to help.