How to delete parts of video with several layers.

I wanted to do a few things, I wanted to make the video appear a bit more 90s style, I found a tutorial for that where you add the various RGB stuff, and offset it slightly, I wanted this to apply to all my clips, but apparently, I can't get this to work by using an adjustment layer. so I had to work with the main video clip.

So I did that, but I still need to get rid of parts of the video. And now I can't delete the superfilous parts of the clip, as it won't let me delete all of the 4 levels,

I want to delete all 4 levels of this marked part, but it won't let me.