Solution
You can use
an array of clusters of arrays to create a similar structure to an array of arrays. The top-level control is an array of clusters, and each cluster contains a single element, which is an array. This technique effectively allows you to store arrays of different lengths within an array.
When you are generating the array of arrays on the diagram, you can do so with a Bundle function to add the cluster layer. Then you can use an Unbundle function when you need to retrieve one of the nested arrays: