Default styling being ugly is often for backwards compatibility with older sites so their look stays as consistent as possible. For that reason opening an issue is likely a waste of time for GP and for the devs.

They also are most certainly quite aware of how the default styling looks in their browser. It wasn't an oversight. That's not to say it doesn't pain them, it often does, but it has been intentional

Usually it looks however the native OS toolkit looks, just like everything else in browser. This is pretty new (and not well adopted) tech so it's not about legacy styling considerations (like, say, the default CSS for text being so awful) but rather that the OS no longer looks the way people want it to look by default.