How can I access the Galarian Star tournament in Pokemon Shield?

So, I’ve been playing Pokemon Sword and Shield, and I purchased the expansion pack in early 2020. On Pokemon Sword, where I had been Champion for months, ended most of the postgame, completed the Isle of Armor, and was currently attempting to fill the pokedex, I finished the Crown Tundra story up until the final legendary clue, which relates to the Ultra Wormhole that appears over the Max Lair. I went outside and got access to the Galarian Star tournament.

More recently, I tried to get the Galarian Star tournament on Pokemon Shield, where I was not yet champion. I completed the story to the same point, yet Leon never called me to invite me to the tournament. So, trying to find the cause of the issue, I became champion, completed the postgame, and completed much of the Isle of Armor. However, I STILL could not get to the Galarian Star tournament. I looked up the requirements to get to the tournament, and I think I’ve completed all of them, but I can’t figure out what I need to do. What steps should I take to get there? If you have any questions about what I have or haven’t done, please put them in the comments and I’ll add the answers to my description.