I am sorry, can you be more specific? On iPhone, in Settings, where? There is no iCloud Drive in Settings, nor Cellular. Can you please write the whole path where i can find what you are asking for? Settings / ... ?
And i don't want to be rude, but i found this irrelevant, as it worked before on the same iPhone before the upgrade to iOS 18. No changes in iPhone settings in last 1 month has been made.