I would absolutely not recommend leetcode for learning Rust. Leetcode has an unreasonable obsession with linked lists and dancing pointers, which are always going to be a bit awkward in Rust. The also used unnecessarily complicated types for some of the Rust code which makes it even worse. When I hit those questions I switch it to C++.

This isn't a knock against Rust. That type of code is more painful in Rust but it's also extremely rare in the real world.

The few AoCs I've done didn't have any of that.