Maybe I'm missing something but you can not see those elements because they don't exist in the current time, probably they exists in any other time. The playhead cannot display them in the current conditions.
Of course, it's the same that you don't see it in the Timeline panel even if you disconnect it.
As far as I know, parenting connection is only affect the screen.
It has nothing to do with the inability to see the start and end in the timeline panel.
The bigger problem is that this is expected to be a problem related to lack of computer resources.
I tried capturing again now, but the number of invisible layers was changed from 700 to 600.
Of course I was able to increase the number of layers displayed by changing the memory settings or clearing the cache. However, not all layers were still visible. And this was only temporary. I'll understand if it slows down my work due to lack of resources. But it is difficult to understand the phenomenon of not being able to completely control more than a certain number of layers.
For reference, I have 32GB of memory in my system. In preferences, I allocated 24GB for all Adobe programs. Currently, only After Effects is running in Adobe programs. However, After Effects is actually only using 5GB~8GB.