Roadmaps and the like can usually be found under the news tab.

https://store.steampowered.com/news/app/892970/view/3056224118622201244

"Take a look at all we’ve got planned for 2021 as we sail through Early Access and continue building the world of Valheim together."

This was the roadmap they listed at release for 2021, they listed 4 planned updates. They released one. They also listed another 9 smaller updates "if they had time", at best they clearly underestimated how much work they needed to complete but it feels like they can't stick to their own deadlines thanks to the like of scope creep and an inability to properly estimate the time requirements of their own plans, it's looking like a roadmap like that will take 3+ years not 1 at their current rate.

Exciting things are planned and i'm keen to see them, but don't wait around for it because you'll be waiting a looooooong time.