Comment by submeta
I literally went out and bought the latest iPhone after my 4.5 years old, perfectly working iPhone 12 was forced to update to iOS 26.2 overnight, and next day was not usable anymore. It turned so slow that I went to an apple store and bought the latest.
How long did you give it? Often various indexes are rebuilt after a major update and that can take a while. It’s running fine on my iPhone 11.