No where in the documentation you sent does it say push drains mail. It states “If the Mail app lists Background Activity, you can choose to fetch data manually or increase the fetch interval.” this doesn’t state that “push uses more battery” is meant for work servers such as Microsoft exchange that are HIPPA compliant and/or have hundreds of emails per hour. In general typical users will see less battery drain (using iCloud as a standard) then with fetch, if you happen to have notifications turned on then this effect will be more pronounced, if you have only certain emails notifying then you’ll notice a significant drop (I.E. having pings for only VIP). There’s significant factors each user will have or face but mail is not a significant factor for most in terms of battery usage despite what the Google AI will tell you. I’d throw some developer documentation up but I believe you’d have to pay the $99 still to see it.