With you and on the same page to that point.
Now I want to create sub‑clips (or zones) from this synced clip.
Yeah that’s not going to work quite how you’re thinking. Even if you group those two together, they are still unique ‘clips’, they don’t become a single clip for the purposes of most clip operations.
You can move them as a group, do some manipulations as a group, even cut segments out and move them around as a sub-group - but they are still a group not a clip, (and yes I know that gets a little confusing when you can ungroup video and audio from a single clip, but that’s a different rabbit hole to go down 
You can treat them more like a single clip if you move them to a sequence and then nest (pieces of) that sequence into your main timeline sequence.
But we still don’t actually give you a way to insert a zone from the timeline into the clip bin the way that we do from the clip monitor for clips. For things in the timeline, the nearest equivalent operation is “save clip part to bin”, which requires you to actually cut the “clip part” that you want to save, not just mark it with a zone. And that should work how you expect if you do it on the nested sequence with your realigned audio in it.
It’s not clear if that is simpler than just cutting the group and directly putting the piece of it where you want it - but really, the main reason to want to add a segment like that to the bin is if you are going to reuse it multiple times in one or more timeline sequences of your project, so it depends a bit on the bigger picture around each case too.
So yes, it’s different to what you are used to. and there’s several different ways to do what you fundamentally want to do (cut up your synced AV into Useful Portions for editing) depending on exactly what you want to do with them next - but it can be done without the intermediate render step - and the interesting question, once you’ve experimented a bit with these other options, is whether there is something useful we can do to make this as easy as possible, without sacrificing the other things that the distinctions between clips and groups and sequences make possible.
The timeline option was originally called “Save timeline zone to bin”, but that’s never been what it actually did, and it’s not quite clear if the reason for that is something deeply fundamental, or just habit and established practice - but this might be something we should revisit and have another think about given all the other UI changes and improvements since then.
Let me know if you need any further clarification.
Ditto : D
I am especially interested in whether this helps you develop even more efficient ways to handle these sort of intermediate composite resources or whether you’ll still see ways that could be improved further.
But basically if you replace “sub-clips” with “segments of a nested sequence” in your description, it should work how you’re expecting.
You might need to spell out exactly what your endgame is here.
