I don’t seem to notice an obvious battery drain, although I have left my Watch Pro pretty default, and set it to an ‘always on display’ clock face and turned off wrist to wake.
With regards to my notifications setup, I have turned on the Outlook, Proton, Tutamail, Gmail, Amazon, eBay, WhatsApp, SMS, Phone, Google & Microsoft’s Authenticator.
What I’d like to see is the Gmail notifications come through more regularly for the app (at the moment it’s intermittent), and a setting tha allows notifications to show briefly past the ‘Always on display’ display mode.
Also, phone calls coming in display sometimes over the Always on display mode, and sometimes not.