Here is a clone that might help.
@meredydd’s suggestion helped me figure it out. On the sub form, from .. import Module1 worked with the layout defined below.
Let me know if this is what you had in mind.
layout:
clone:
https://anvil.works/build#clone:QVVWQ4L7CYCGYN5O=4L5UTMXQUBW72OCPWO6X3BYO