Normally I wouldn't think the "we" thing mattered, but she then awkwardly tried to correct it which made me think of Wontons. And the amusing thing about Dizzy is that she advised Sakana against hiring Shiina for that incident (despite the fact that she would be taking on a new persona). Like of course its not as clear cut as "my boyfriend" but the details are in the reaction and normally I think she would have just said "We" and went with it. I don't think anyone should be surprised if this is indeed a boyfriend yab but at the same time she has kind of built her whole identity on "not getting a man" so its just kind of funny all the way around.
What it probably is is that ok, pretty much all Vtubers have a SO and I would say that it wasn't strictly a boyfriend yab but for some reason she took it as one and awkwardly tried to fix it. It would be funny though if she quit her job because she got a sugar daddy I suppose. But again thats all speculation. Gut instinct tells me that yeah this is a boyfriend yab, but I wouldn't bet on it really.