For the initial size you’ll of course have to trust on what Atlassian’s REST API gives you and that might or might not be what the given macro has specified in it’s descriptor.
For resizing the nested macro dynamically whenever it’s calling AP.resize you’ll likely need to implement this in your wrapper macro via Atlassian’s simple-xdm bridge. (See my other response here and especially the part about auto resizing iframes in the readme of the linked simple-xdm repo)
Note that I’m saying likely, because I haven’t actually tried this myself - but if you approach it from a technical side: how else is AP.resize() going to have any effect? It definitely needs to trigger something in the context of your wrapper macro that then adjusts the size of the iframe, and simple-xdm seems to be the way to do that.
Cheers,
Sven