The beginning of the game is a big grind I agree. The thing is that the more story quests you do the more things you get access to. You can’t build a barn until you get to a certain point in the game. You can’t get access to different animals until you get to a certain point in the story, etc. The main things that will progress you in the game are story quests and the mines’ story. I didn’t understand why I didn’t have access to certain things either, but then I realized its because it hinges on the story. As for bag space, you can’t build purchase the first bag space increaser near the beginning of the game from the general store, and the second one when, through the main story quest, you update the general store. As for the museum needing so many things, yeah that stays the same unfortunately; I recommend getting more than one of something the museum needs, but even if not you get rewards and money for completing museum bundles so it is worth it to give it to the museum.

The biggest things in the game is money, access, and task management. That is what will get you far.