I guess theme for the anniversary will be like alchemy and related to it things. That's why night watch's skin is called like that, because the point of alchemy was to make something that can transform anything into gold and revive dead people.
I think the theme for season 33 essence 1 is based around the Olympics, they did this with Galateas Checkmate essence in 2020 aswell as making an entire event on it. This year it's commencing in France (hence why you can see the Eiffel tower in the background) and they're starting on the same day as the new season is.
I hope they release some of the old crossover content again. I lost my old account and I had to restart again months ago. Had so much on my old account too 😭