I think the node you're looking for is array loop not normal loop. Normal loop will "loop" back the output to be used as input multiple times. If you want to process each value in an array, you should use array loop.

Normal loop will "loop" back the output to be used as input multiple times.

I know, that's why I was adding the resulting surface on the array, then returning the array so it can loop on it several times.

If you want to process each value in an array, you should use array loop.

I managed to make it work with the Array loop, but I expected both methods to be valid. Also, what I don't like about this method, is that I have to "preload" the array, resizing it to the desired size (even if each entry is empty).

I strongly feel this approach should work, and if it cannot work because of limitations, there should be a restriction not allowing you to do it: be it not outputting an array, or not being able to use array operators inside the loop.