I'd like to be able to tie symbology classes to page queries.
For example, in this map series, I've set it up so that the features related to the active page are in dark red, while the other features are in light pink.

To do this, I used 4 layers, two for each feature class. Each layer has a page query:

What I'd like to do instead is set the page query as part of the symbology:

This would be similar to using an Arcade expression:


Except that this would be dynamic. (Side note: as it stands, changing an Arcade expression overwrites your symbology, so definitely trying to avoid that)
Bonus:
I think a great expansion of this functionality would be to also be able to maintain the other symbol classes that you normally would, but just have the active one sit on top, in addition to a simple True/False as described above. For example:

In summary, being able to set up symbology to match the page queries would be a great time saver and make Table of Contents a lot more easily organized.