It took me about a week to finish the main story. 30-ish hours maybe? Put a lot of time in over the new year's 3 day weekend.

Now I just need to dig into the post game. Yesterday I started the expansions and they're a lot of fun. Like you said, more wild areas to explore. I'm liking the story of these, with the Calyrex and the legendary bird hunting.

Not sure how I feel about the Dynamax caves. The roulette aspect and not being able to use your own party to face a legendary is kind of off putting. Can't tell you how many times I've lost one of those because the NPCs came equipped with Magikarps and you get the 4 KO maximum before the level ends.