Learning lifetimes in Rust I've found to be quite like when I first learned pointers in C/C++. They're the hardest most enigmatic thing in the world until at one point something suddenly "clicks" and they just make sense, and you'll wonder how you ever struggled with them in the first place.
For me the actual toughest thing to learn were procedural macros, and the reason for that is because actually implementing them is more on the niche side of programming compared to using them, so most "learning Rust" resources just hand wave them away, and their usage is so special cased that all the limited learning resources around them target specific niche use cases that might not be what you in particular would use them for.
For me the actual toughest thing to learn were procedural macros, and the reason for that is because actually implementing them is more on the niche side of programming compared to using them, so most "learning Rust" resources just hand wave them away, and their usage is so special cased that all the limited learning resources around them target specific niche use cases that might not be what you in particular would use them for.