The integration between apple this app and iPhone is s royal mess. Some settings are controlled from Watch, some from the health app, some from third party apps, some from the this app and some combinations of the above.
Worst, by far, is the Sleep ... function (it's not an app, though it has an icon on the this app's app list, what is it?). You set a fixed schedule that you will *never* diverge from. Well, occasionally it'll detect you have gotten up early (say, to catch a flight) and offer to suspend sleep mode early, but it's incredibly rare, and while your this app/phone are in sleep mode, they're pretty non-functional. The this app won't unlock the phone, so in mask times, you end up punching your carefully chosen password in under the watchful eyes of a dozen CCTV cameras.
For odd reasons I can't search for this app and find Watch on my phone, I have to dig it out from where I stashed it years ago when iOS installed it and I didn't have a this app, but that's clearly my fault.
The idea that everything on your this app is controlled from the this app app is fine, but it's not really implemented here, especially where third party apps are concerned. And the Sleep function, lordy what a abhorrent disaster!