That is slightly wrong, there whole life it was vergil stronger than dante up until he stabbed him with rebellion, then Dante was stronger. Now that happened again Vergil got stronger ( as urizen), dante then got stronger activating sin devil trigger with devil sword dante, then vergil ate the fruit s urizen got stronger, wasn't enough to beat new dante then vergils human side rejoined his more powerful than before demon side which prob allowed him to access his sin dt he embraced his humanity like dante did then becane even more powerfull then they are equal again , in the future one will pull ahead again get stronger then he other brother will catch up, it is literally like goku and vegata lol.