> in Rust you have to do some shenenigans with things like RefCell<Vec<Rc<RefCell<Item>>>> which is simply not very ergonomic

The entire raison d'être of Bevy and the reason it is built how it is is that the ECS eliminates that. If your Bevy code contains something that looks like that, you are using it very wrong. You put the data in the ECS, and any gameplay code goes into some system that uses the queries to pull the data it needs out of it. If you need something like a backreference, you don't add one in an unholy tower of refcells, you just use a different query.

If you wanted to argue that a soup of mutually referencing objects is easier to deal with than having to use a query system, I'd disagree, but you'd have a valid argument. What you posted above just highlights that you don't know much about bevy.