Custom Event On Character Movement Begin Update?

I’ve got the Custom Event for OnCharacterMovementUpdated working just fine, but I’d like to add an event that fires immediately before the inherited character movement component executes. I’ve tried adding a timeline and setting character movement as a prerequisite component, which works to a degree, but doesn’t guarantee other actors in the same tick group won’t fire in between that and the character movement update. It seems it would be best to not have to add prerequisites to everything in a level versus a single custom event in a character.

The goal is to be able to scan for objects that movement will collide the capsule component with or otherwise modify velocity, and then make changes prior to CharacterMovement updating if necessary. For example, if a character runs into a high step that I want them to go prone and slide onto due to their velocity, I want changes to enable that before velocity is modified by a collision with that object during the CharacterMovement update. Can this be blueprinted or does it have to be done in C++?