Move over 100 layers on timeline without leaving keyframes behind

Hi, I'm using AE 24.4.1 and I have to shorten a video a bit. This is a 5 minute educational video with 115 layers. The client asked me to cut a line of text off of one screen and to cut out the section of narration (where I read the text out loud.) I've used "Split Layer" to remove that section of narration and I moved the rest of the audio layer to the left on my timeline, thus shortening my narration track.

I now need to move all 114 layers to the left on the timeline so they will match the, now shortened, audio track. When I move all those layers I need the keyframes to move with them so they keep their position relative to each other. For example when the opacity of one layer drops from 100 to 0 the next layer's opacity ramps up from 0 to 100 creating a smooth transition.

Am I going to have to select 114 layers, *and* their keyframes one-by-one in order to move them all in the timeline? I've seen people suggest using a null object but I'm not repositioning things on the screen. I'm moving each layer's position on the timeline. So, am I going to have to I have to highlight each layer and it's keyframes, one at a time, and then try to re-match the transitions 114 times? Seems like there should be a quick way to select all 114 layers and their keyframes at once. Do I need to pre-comp everything and move the whole precomp? Will that strain the resources of my (old) Macbook Pro?

Thanks!