On October 1st, 2019, an update was made for playing online with friends, minor changes and bug fixes.
Added "Play with friends"
Added features to "Nearby Play"
Added "LAN Play"
Added a list of Official Makers in Leaderboards
...oh. I see Nintendo still doesn't care about the feelings of Mary O. fanboys like me. (Unless Mary O. is one of the "official makers" like she was in the first SMM, but I think we all know that won't be the case.) :(
I know I complain about this a lot, but seriously, how come almost every character from the first Super Mario Maker's interface - Undodog, Yamamura, even the likes of Mr. Eraser and Coursebot and Soundfrog for crying out loud - is not only in Super Mario Maker 2 but has also been given more personality than ever before, but Mary O. has been replaced and Nintendo STILL hasn't so much as acknowledged her existence or told us why she was replaced? :(
Considering how the Super Crown and Peachette keep appearing in more and more games even though I thought Nintendo learned their lesson after all those Super Crown memes, I can only assume that someone at Nintendo said "Let's NEVER put the Super Crown in another game again; it's making us look bad" and someone else somehow misheard "the Super Crown" as "Mary O."
(I'm joking. Kind of.)