The stopwatch does only work with the screen on, but it also keeps the screen on so it doesn’t stop working.
Notifications don’t stay there… You can see the last 5 notifications if you swipe down on the main screen.
You can enable the HR monitor and exit the HR app. It will show on the watch face if it supports it. The HR sensor only works if the screen is on so it doesn’t drain the battery otherwise. It’s not great and takes a while to display the rate.
Idk about the step counter. It’s the most useless feature on any smartwatch so I never use it. What does it count as a step? What’s the use of counting the steps? You know how you did or didn’t walk…
I don’t have many other fails. The alarm works great, the flashlight gets daily use and I use it to control the music app on my phone. It does everything I need for an open source device, which is the primary reason I have it.