I know this is a really old thread but I am having the same issue.
Basically I have almost 200 layers connected to one controller that holds a few effects like Fill.
This increased my render times dramatically once I setup all the expressions! I just need the user to be able to pick their color scheme and then be able to ‘lock’ it in without the expressions active anymore.
Is there any way to do this? Maybe some form of batch expression to keyframe script?
Thanks