Happens on numerous apps for me (even though i've disabled all of the sleep options for these apps).
For instance, Twitter - i have instant notifications for certain sports journalists, very useful on game days. Side by side - iPhone and Galaxy S10+, iPhone twitter notifications arrive straight away..... however, unless the Galaxy is unlocked with screen on, the notifications don't arrive until a few minutes later, or until i wake the screen and am met with a bunch of notifications.
Sky News (breaking news) another example.