My bad, the effect was at 3:48 (I wrote this post on my phone so it messed with my typo a bit)
I solved it yesterday after doing something very basic, I’m posting it here in case someone finds it useful:
The issue:
Matching a layer’s movement to the movement of a trimmed path.
1-Set keyframes for start and end of the trimmed animation
2-Copy the path of the trimmed shape and paste it in a Null’s position
3-Expand the time of the Null’s position to match the start and end of the trimmed layer.
4-Check on Null how many frames it moves per second
5-Apply to the layer
6-Precompose and adjust timing if needed/desired.
It was a lot easier than it looked; it may not be the most elegant way but it gets the job done.