I’m not sure how you’d programmatically fill that in via the CMS.
This may be a fringe need that hasn’t been created yet. Actually seeing CMS Collections inside a Collection is new to me, so, yeah, what you’re asking for sounds like a byproduct of this new functionality.
What might work, to work inside the capabilities of the current Webflow product, is to alter how you’d construct each page.
For example, perhaps instead of having Published Games be a collection, you actually (I know, I know) make Published and In Development a toggle or drop down item in a Collection of Games. You could then filter which are shown in any list. Consequently, when a game moves from Development to Published, that would be a dropdown change, instead of an entire recreation of a “DB entry”, if you get my meaning. Hmm. This may not exactly solve your needs, but perhaps re-thinking the structure may make more sense.
I hope this helps.