The Problem

Currently, when comparing regions or putting them into a HashMap or sorting collections or basically anything that requires consistent equals and hashCode result

A Solution

Proper equals and hashCode methods for comparison of regions

Alternatives

Writing your own wrappers to add equals and hashCode methods

Anything Else?

No response

You say "sorting collections" which implies you want them to implement Comparable too, but I think that is right out -- we don't have any consistent way to sort worlds really, that wouldn't just be an arbitrary sorting.

As for equals and hashCode, I suppose we could but the behavior might not be as you expect since you don't specify a specific use case here. Should two regions that cover all the same block points be the same, i.e. if you had a cuboid region and a poly2d region that covered all the same blocks, are they equal? Depending on your use-case the answer might be yes or no. How should world equality be considered? Should it be considered at all?

My current feeling is that since we have no use-case for it, we should not implement it at this time. But I'm open to discussion on it.

I was facing the issue of Map and Collection #contains returning false even if the region was inside the map or list
it would only return true if the exact instance of region was contained, but because I use cloned objects for immutability I can't check whether it already contains it or not

in my opinion, a simple comparison of the positions and region class is enough

as for the comparable I see your point and in that case I was simply able to implement my own comparing logic (in Stream#sort) so no real problem there

There are issues with ignoring the World (technically incorrect, depending on what you're trying to do with the regions). It's possibly you may be better off using a record with the immutable properties you want, rather than cloning our regions everywhere.

In most cases if you want to compare regions you also want the worlds to be compared
If you don't you can just compare the points of the region
So my suggestion would be comparing all points and the worlds and obviously the type itself
I am not sure whether the world implementations have proper equality checks, depending on that it would be also required to add ones there

WorldEdit barely uses the world. I think in the actual WE implementation itself, the World is only ever used for clamping bounds. Thus your idea of "most cases" is going to be entirely up to where you're getting those region objects and what you're using them for.