No, Uchū means "space", "universe", or "cosmos" depending on the context. And in the context of Drawcia drawing in "every space", it just means "space". Not "universe", it would be crazy if the game said that. Drawcia was drawing in "every space" around in the sense that there were no areas around not being affected by Drawcia, just to be properly descriptive.
Yes, she was "turning everything into a world of painting",
but only in the sense that this was her goal. We don't know how much she actually managed to turn into a painting before Kirby chased her off. Heck, we don't even know for certain if she really wants to turn the universe into a painting, it's just a likely assumption.
Furthermore, we don't know for certain if this would scale to AP by itself, she's lucky to have also sent a wave destroying interstellar parts of the World of Paintings to complement her Tier.
For what is worth, Drawcia's feat are very weird, and it would not surprise me if she did actually turn the universe into a painting. I will tell you if she did in 10 years if I ever buy all the Jpn. guidebooks for her game. Based on the information we do have, we have to say she didn't do it.
The best argument you have is that statement saying that she turned the world (Sekai) itself into a painting, and "world" could potentially refer to the universe in this context. Couple that with her motivation being jealousy of "the real world", which is another word for reality itself.