The "caution battery low" notification is hilarious — the battery life on Apple silicon is so good I've literally never gotten one of these on my M2 MBA (which isn't even the current generation). They're obviously grasping at straws if they're pretending that this is some sort of common annoying notification.
Absolutely. The notification is neither common nor an annoyance. It is just the kind of notification you would want to get. Probably going into DND mode wouldn't prevent it from popping up, since it is so important.
Obviously what a Real OS should do is not notify about low battery at all and just suddenly shut down instead. Whereas it's absolutely essential that users get notifications every day to switch browsers or subscribe to Microsoft 365.