Historically there has been content added to all levels of the game, so chances are good. That said the immediate future seems to be focused on continuing progression.

I'd like to imagine that there would be the remainder of unfinished progression added to to the game over time with a sprinkling of of content added to earlier game as seen fit.

Then after everything is in place, some additional content where needed (mini bosses , ocean diversity, etc, and then final balancing , bugs, and then special features like difficulty slider, world gen sliders etc.

Then hopefully Valheim 2, or some other project from this studio.