I just got a new Pixel 6 last week and got Graphene OS onto it. The battery died, and when I put it on the charger it follows this cycle:
- It'll say "your device is loading a different operating system"
- Shows Google logo
- Shows Graphene OS logo
- Might show lock screen for a bit
- Shuts down
- When I press the power button, it shows the no battery icon
So then I charge it and the steps repeat.