Your question isn’t well stated and I think it shows an unclear understanding about cosmic horizons, the consequences of the speed of light and in general and the notion that the universe has no center. I could suggest a few videos. “If objects created after the CMB are outside our observable universe, why is the CMB our temporal edge” makes no sense. First of all, it’s not IF objects created after the CMB are outside our observable universe. Objects ARE created after the CMB within our observable universe and outside our observable universe - no “If”. The CMB is usually used as a temporal line in physics but for your question you are really asking it as a distance line - “a horizon line” but you need to understand that and not say “temporal edge”.
You can’t compare a distance thing (objects created outside of something) to a temporal time thing -which seems to me to be how your major confusion is arising.
Fundamentally stuff we can’t see is because it’s in parts of the universe that was moving much to fast to send light that will ever reach us. Its not about time as much as physics doesn’t let matter/energy travel faster than the speed of light but it allows space to expand faster than light. You probably know that but keep it in mind.
To get to nuts and bolts then, the distance limit of the observable universe is 46 bly (billion light-years) away. “Today” there are galaxies, at that distance, that are 13.8 billion years old, just like here. Where light generated during the Last Scattering Event, for Earth observers, is today is somewhat closer still probably 30 bly away or so (I'm not going to do the math) and...again there are galaxies there that are, unsurprisingly, 13.8 billion years old!...just like here and this is because “the universe has no center”. And maybe it would also be useful for you to realize, observers there see us as the source of THEIR CMB! Think about your question a little more now and it should resolve.