Wear OS "offline" or bluetooth off mode

I understand from a previous post by @jiri-urbandroid that it should be possible to use Wear OS watches in an offline (no bluetooth) recording mode by the following:

  1. start sleep tracking, let the watch connect to Sleep as Android
  2. now you can turn off bluetooth
  3. at some point during the night, you need to turn on bluetooth again (using perhaps some automation app like Tasker)

This does not actually work in my trials, but it would be really useful as having bluetooth off would lower battery usage on the watch.

Could this be investigated/added?