@HeeroWingZero I think it makes sense for you, as the uploader of this character, to pay attention to this.
Did not know about the other vtuber named Ruruna, though in that case just ruruna_(virtuareal) should be fine? I think someone who's more familiar with the group should decide on a new tag if necessary since she's specifically a part of Virtuareal LINK like Nox and Karon, which is why they have (vtuber) qualifiers instead of (virtuareal), and why they're tagged under both Virtuareal and Nox Official/Karon Official.
I don't think this is anything to be concerned about. The Ruruna you link to not only has been retired since February 2020, but also, as the article notes, her model seems to be one of the default ones in the Hololive software fans can access (just with the hair and eye color changed). Additionally, checking her social media, she has (at the time of writing) 1k followers on Twitter, and nearly 2k subs on YouTube. For all intents and purposes, the only reason she has an article at all on that Fandom/Wikia is because a fan of hers made it, most likely.
If we don't have any fanart of her now, we likely won't have any in the near future (and if we do, it's likely been confused for fan art of the default model). As such, the tag can easily be used by this Ruruna, who is actually still active.