I think there are more than one reason as to why DmC's cursing comes off as juvenile whereas DMC5's... less so (not gonna say completely not).
First of all, it's Nero. A new character completely separate from Dante, and was established as a vulgar boy in 4 itself. It incites less of a reaction when it's not a version of an already established character. So
@Sparda's rejected son is right when he says that if it had been Dante doing it, it wouldn't have gotten as much of a pass. I, for example, don't really like Dante swearing in the anime.
Second, context plays a part in how cursing comes off. Swearing in itself is not a problem. It often becomes one (not always, but more often than not) when it's the purpose of dialogue, rather than be a tool in the dialogue. An example of the latter in the reboot itself is when Dante teases Mundus comparing him to his "little demon bitches". It works there cause there's good enough context. A simple one, but good enough. He was actively trying to make him lose his temper. There, the cursing is a tool and not the protagonist or the point of the exchange.
But most other times, it's the other way around. "- You are dead, just like your whore mother. - Whore mother? I don't know my mother but if you're calling me a son of a bitch you wouldn't be the first.", "The world is at last your bitch. As am I.", and the whole succubus exchange are all instances of dialogue or entire scenes being built
around the cursing, rather than the cursing serving the dialogue. That's when the swearing becomes cheap and eye-rolling.
So when you take the iconic F-bomb from DMC5 and compare it to the iconic F-bomb scene from DmC, that's where the difference lies, mostly. Lore wise, Nero's "**** you" is an expression of pent up anger and frustration towards his father who disregarded him and didn't even know he existed, Dante's "**** you" is literally just a swearing contest with some throwaway boss that has next to no significance to him aside from being in the way. It was shock value and shock value
only, with no other subtext to it.
Could both moments have been done without the swearing and was the swearing there just to make a cool moment in both instances? Sure. The point is that, once you do end up deciding to put the swearing in them, one of them works better than the other with it because the rule of cool isn't the
only factor at play.
Lastly, even if you ignore all that, and get down to the rule of cool factor alone, Nero's F-bomb in DMC5 ends up being enjoyable for a lot of people, unlike Dante's **** you-off, because it's just more self aware. The DT explosion and Silver Bullet starting off right as he does it, has an impact and you can have fun with it. It's flashy, the game knows it and rolls with it, not in a mean spirited way like the succubus exchange but in a more whacky, fun loving way. It's a good hype moment, doesn't make people dislike Nero, makes em have fun.