is there a battery indicator for charge level for official dock?
No. It works the same as the PS4 controller.
Basically, when you put your controller on the dock and when you turn on the power, your controller will start to slow blink orange and black. Once the controller is done charging, the orange light will turn off on the controller. That's how you tell if the controller is done charging.
I have those old 3rd party PS4 controller chargers, the blue LED light is constantly on and will only show red if the controller is charging and then change back to blue when it is not. It was quite distracting at night since my console setup is in my room.
End up, getting the official PS4 dock. Cos at the end of the day, the controller already shows the orange light if it is charging and turns the LED off when it is done charging. So it's completely unnecessary to have any LED indicator on the dock itself.
All in all, it seems that on the controller or 1st or 3rd party dock, the charging indicator only shows 2 things. Either that it is charging or it is not. There's no indicator to tell you what percentage the battery is at.
However.... If you use something like DS4Windows and you leave your controller on, the app will show the exact percentage the controller is at even when the controller is charging. So if it matters, that's one way.
Honestly, I don't see any reason to do that though. I just throw it at the dock, ask Alexa to turn on charger and charge my watch, phone, controllers, toothbrush, shaver, earbuds all at the same time. Then automatically in 2.5 hours, my smart plug will turn off the power. 2.5hrs is roughly the time it took for the slowest charging device I have. It's the old PS4 controllers.
The current PS5 controllers seem to have faster charging. So I might have to tweak the timing to turn off the power a lot more sooner. So no devices will end up being overcharged for long.