Even with a 5" screen, it was bigger than for example iPhone 17 in every single dimension due to its hefty bezels (and not insignificantly so; iPhone 17 is closer in width to iPhone 13 Mini than a Dell Streak).
Screen diameter is in general a bit misleading figure for phones from different generations as "full screen" phones tend to have a taller aspect ratio and hence larger diameter even with same body dimensions.
The GSM Arena review is mostly about the confusion of whether it should still be considered a phone at this size. Ultimately they decide it's just too damn big for a phone.[1].
It had a 5" screen.
[1] https://www.gsmarena.com/dell_streak-review-531.php