Learning Rust in 2023: A Call For Discussion
Rust has a steep learning curve.
Once you're fully immersed in it, as with any skill, it becomes very difficult to properly remember what exactly made Rust difficult to learn. In a general sense, it could be the fact that it exposes the average programmer to some new features, most of them not present or only just beginning to show up in mainstream languages, and some that are close to unique.
Source: Learning Rust in 2023: A Call For Discussion, an article by Eshan Singh.