Yep the learning curve in this game is quite Strange. I also found it confusing in the beginning what comes next as my first map was pretty ♥♥♥♥♥♥ up because I had Plains super close. I had to sail quite a bit for my first swamp, and I didn't know what to do with the mountains at that time.
The only thing that showed me I was wrong here was my death. Since at the time I used neither wiki, nor forum. And that's quite a deterrent, at least it was for me, which is why I concentrated for a long time on meadows and dark forest and built~ until I joined a server because it was super boring alone.
Swamp was scary at first, but we had potions and at the beginning there were always at least 2 of us which made it easy. Mountains were annoying, and Plains, fuling-camps was a pain in the ass. My friends died so often, although we tried to pull the mobs as best we could individually.

Eventually you get used to it but ... it can be exhausting and not for everyone. If I had played the game alone, I would have quit very early.

I once read that the plains are so hard, because this is atm the only "endcontent" of the game. So another attempt of the dev's wto stretch content with cheese methods.(as I said, I have only read that, can also be wrong and this strong curve is intentional)
Here in the forum probably most will say that the game is not hard enough. Another reason in my opinion, for more customization options.