After effects - how to put multiple sources on the same layer line? or how to reduce the scrolling of the layers panel? Competitor software can put multiple footage in the same layer. I think this is Pinnacle, but I've seen this also in Magix (I am not a professional, this is the kind of consumer software I've used in the past):

Instead, it appears this is not possible in After Effects. Am I wrong? Is there a way to do this?
As a result, nearly half of what I have on my screen is just gray lines. Either that or endless mouse wheel scrolling. I have over 5 million pixels on my screen, but they are just used for gray. I think this is horrible UI, and I'm looking a way to improve my user experience. What are my options?

This is totally making me go cross-eyed and giving me headaches. I just can't believe this is what you folks have to deal with. There's got to be a better way. Thank you.
P.S. I cannot pre-compose otherwise I lose the ability to snap. Tried that – didn't work for me. Any suggestion?
Video editing (cutting) is best done with Premiere Pro and animation with After Effects. Both are complex software tools that require lots of training. You should invest more time in training or maybe choose different products, if they simply don't fit to your style of working.
Create a sequence in Premiere where you can easily have as many clips in a track as you want. Create a new sequence where you insert this sequence (this is called nested sequence). Then right click on the inserted sequence and select Replace With After Effects Composition. When After Effects opens you will see that you get a composition with only one layer.