Subflow as SplitInBatches alternative

The idea is:

This is where the idea comes from:

It would be practical to create a subflow. Not as an extra flow per se but as an extra group.
Nested Nodes | Vue Flow

My use case:

It would simplify the editing very much. SplitInBatches it mostly very complicated to use.
The nested flow could also have a batch size here.

I think it would be beneficial to add this because:

It solves the problem with the complicating SplitInBatches.
Maybe multiple nesting can also solve the problem with multiple SplitInBatches.

Possible related thread:

@shrey-42 Yup has a different name but I think that goes in the direction.