Iphone12 undoubtedly world best smart phone
The $799 iPhone 12 is the standard model with a 6.1-inch screen and dual camera,
Although it is little bit expensive but finest quality
while the new $699 iPhone 12 Mini has a smaller, 5.4-inch screen. 
All the iphone model is very much attractive
 with availability beginning Friday, October 23. 
I think you mentioned date is corretc
The Samsung Galaxy S21 has more cameras than the iPhone 12, plus more RAM, a bigger battery, a slightly larger screen, a higher refresh rate, and more storage in the entry-level model.
Samsung Galaxy S21 also good phone but I think not better then Iphone12
there is a lesser risk of downloading apps with malware on iPhones than with android phones.