I’m currently working on something very similar to what you described. It addresses exactly the problem layed out in the Apex.AI talk, and altough i had not seen this talk before i think i arrived at a very similar approach. My solution is not open source yet, but i plan on publishing it (once my masters thesis is done, which this is the main part of).
I put a small summary of the issues and approaches on my website: Deterministic ROS2 Callback Scheduling :: Jonas Otto