I don't get anywhere close to 3 hours. My battery goes down almost like a ticking clock. 1% per minute, sometimes faster.
The other issue I'm having is my MBP 16" won't charge and will sometimes report the wrong battery charge level.
For example, yesterday, when I plugged in the charger the battery indicator, which showed 78%, briefly changed to the charging state, then I got the "ding" that you hear when MacOS doesn't recognize a usb device, then the charging indicator changes back to battery mode. I tried the other ports and none of those worked either. Then I rebooted at 73%. When I booted back up it was showing 1%.
This morning I have the same issue. Started at 98% and refuses to charge. In the last 8 minutes I've dropped to 88%. Now I'll reboot to try to get it to recognize the charger.