To some extent we'll know based off how Penta is treated.but the fact that she still needs work on her English may give him pause.
But even that's not a great comparison considering Steph wants to learn English to use for her promos whereas Penta can speak English but he'll never be comfortable primarily using English for promos.
As a fan of both too, I would also agree tbh atm. Giulia came in with way less experience than Asuka and Iyo, so she hasn't adapted as quick as they have. She still has to find her groove really. With the WWE having 3 veteran Joshis already on the roster, it was always going to be harder for her to stand out. I think she will eventually get there as long as she remains motivated and Paul actually sees some value in her.
To be fair, even though Giulia is our NXT champ it feels like Steph has been pushed onto screen and has more exposure. Like without even trying I've seen far more Steph clips on YouTube or media interviews than Giulia.