I noted this in my big long issues list as well. I agree that it's confusing where you're supposed to go. I did a lot of the same things too. I
At the start the main quest seems to be directing you to Silverglen, so I did that and joined the Immaculates, but realized something was wrong when I was sent to an area with level 14's. I went the other way and encountered a lone level 12 orc scout. I beat the fight, but the difficulty of it convinced me that was also the wrong way to go.
I kept exploring, and then found the actual direction you're supposed to go is the white witch's cabin. The problem isn't that you're not exploring properly, it's that the game gives you signposts which go the wrong way.
Larian tried to make an open world, but in practical terms, the difference levels make had it turn out a lot more linear than they were expecting.
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About the barrier-removal spell
Oddly enough, if you SUCCEED in solving the mushroom's riddles, you get a WORSE hint than if you FAIL. If you pass, all the mushroom says is "some wizard wanted to make the barrier go away". That is IT. Nothing else. From that, though, you get a quest log entry that says "Maradino might have stashed a barrier-removal spell somewhere around the forest".
First, that doesn't follow from what was actually said. Second, it's not helpful.
If you fail the riddles and have to take extra steps, and threaten the fungi, then they cough up something along the lines of "I think maybe it was hidden between the two troll-guarded bridges". That IS helpful information, but it doesn't make it into your quest log!
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I can also agree that the Death Knights stealth section is problematic, and those who can't sneak and sneak fast get caught easily.
