Hi Benjamin,
On reflection you are correct, in this case that function likely won’t help you. Chaos disables the code path for a _single_ rigid body with a constraint, it would turn off an inactive island. The idea of monitoring linear speeds is reasonable enough - the other way you could do it is to monitor movement within an area, and if it doesn’t exceed a tolerance (ie X stays between 9.95 and 10.05 for 2 seconds) value in all 6 degrees of freedom then it can be put to sleep - that is used sometimes specifically for jitter in physics.
I have taken a look at the default manny and you are correct it doesn’t settle as standard, I’ll reach out dev wise to see if this is known and what the expectations are for an example asset.
All the best
Geoff