Just finished the Crown Tundra, it's definitely the best part of Sword and Shield. It's emphasis on unlinearity and collecting Pokemon and how they intertwine the story with the open area is excellent. I do think there could've been more variance in the story quests, but this is definitely a good direction for 3D Pokemon. I really hope they continue this new direction for the next Pokemon generation.
I also really enjoy the Dynamax Adventures mode, it's honestly a much better way to collect strong and shiny Pokemon compared to normal dynamax grinding let alone the legendary Pokemon. I have only done it with AIs so far, which I do personally find better due to that making it more challenging and requiring more strategy from you specifically. The AIs can be infuriatingly dumb sometimes, though.
Crown Tundra also gave me my second favorite Pokemon, Pheromosa! Unfortunantly I can't find a good team that works with both Pheromosa and my absolute favorite Pokemon, Poliwrath, though.