I had to search for "focus mode" to learn what you were referring to, so forgive me if my understanding is incorrect. Isn't that a Win 11 thing? It looks like a kind of do-not-disturb mode?

How does that intersect with browser push notifications? Another advantage of email notifications is that the email notifications won't go away if I don't pay attention to them for a long while.

In any case, I don't use Windows except at work, where this wouldn't be an issue anyway.