> In a custom language, this can be implemented very easily following the approach outlined in this paper: Accurate garbage collection in an uncooperative environment.

Cheney's algorithm and conservative roots don't mix too easily, as you cannot move conservative roots: an integer which looks like a pointer shouldn't be changed by moving. https://dl.acm.org/doi/10.1145/2660193.2660198 has an overview of algorithms which don't move conservative roots (including never moving, as in Boehm-Demers-Weiser).