The Ace Attorney 20th anniversary is one week after the Final Mr. Sakurai Presents for Super Smash Bros. Ultimate reveal - EventHubs

Phoenix Wright: Ace Attorney was originally released on October 12, 2001 on the Game Boy Advance in Japan.

Does this mean that Phoenix Wright is the secret fighter behind Challenger Pack 11?

As of right now, there isn't even a single reference to Phoenix Wright or the Ace Attorney series in Smash Ultimate, as a Spirit or otherwise.

However, characters have traditionally not been revealed or released for Super Smash Bros.

ARMS was originally released on June 16, 2017 while Min Min became a playable fighter in Smash on June 29, 2020.

If Phoenix Wright did join, he'd be Capcom's 4th rep in Smash Ultimate.

As of right now, there is no third party company that has more than 3 playable character in Smash Ultimate.

However, it was originally Capcom that broke a similar trend when Street Fighter's Ryu joined Mega Man in Super Smash Bros.

Back then, no third party had more than 1 character playable in the Smash series4