Ok, I'm going to say a thing and it's a thing that people have gotten super pssd at me for saying it but I'm going to say it and I am and will continue to hold to it.Vergil is a frustrating case to deal with. DMC doesn't have dragon balls to fix his mess like Vegeta. Nobody can "humble" him except his relatives but unfortunately Vergil dumb everyone down when he's nearby. The most offensive is his cruelty acts in game actually rewarded him. A manga where he pitied himself more than pitying his mother getting killed by demons. Just too much...
I think the big issue DMC has for its canon, especially right now, is that out of the people making it nobody cares what they did before; they are always changing things and throwing out this and that irrelevant of how important a part of the game it was introduced in it was. If it's in the way out it goes. This is why Dante and Vergil are no longer identical twins, it's why the original chronology has been scrapped, it's why Nero is the new lead and Dante is second fiddle in his own series.
I mentioned this as a prelude because it's relevant. So, with all the being said, the biggest issue that we have with Vergil is that there is too much DmC in DMC5. Beyond just him suddenly having DmC powers, which were never there before, they flipped his (no pun intended) motivations to match DmCs. Now Vergil thinks him mom didn't love him like she loved Dante, which is what he said to her in the Vergil's Downfall expansion. Dante confirms this new interpretation in 5, too. That was never how he thought about his mother. Vergil's reason for wanting power was because he was never able to protect his mother. This isn't a theory or speculation, this is a fact. If anyone needs to see it in print you can look up a translation for the book Trinity of Fates where the makers specifically say that the one feeling that unites the brothers is their want to protect their mother and how their failure to do so lead the to their respective paths. Oddly enough, they were very specific about how the parents loved their sons equally.
Well, whatever, because that's gone now and it's the DmC thing now but, if the pattern holds, then that's going to be gone as soon as it becomes inconvenient to the next thing, so getting attached to anything might be getting too optimistic. Vergil isn't going to get 'fixed' in any way you might find satisfactory if they don't have rules that they adhere to in their world. Tone, rules, principles and motivations are pretty fickle here.