Basically the API is not stable/mature yet to support third-party development. As noted, you can reverse engineer it if you choose to. Doing so does mean taking the risk that if/when there are changes to the API, you may experience issues (there won’t be advance notification for any changes until it is supported/documented). Also with Device Health be aware that if a device should get into an OFFLINE state incorrectly, and can’t get back ONLINE, deleting and re-adding the device may be your only solution.
I really want/wish this could be documented and supported, but it’s not there yet. I have no timeline when it may be.
tl;dr - reverse engineer and use as long as you are OK assuming the risks with doing so.