After effects - how to put multiple sources on the same layer line? or how to reduce the scrolling of the layers panel?
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.