Oh, I'm sure, and it wasn't meant as a slight to how you were going about figuring how you wanted to play, it was merely meant to emphasize the point that, even as a veteran of RPGs and this concept, AoD takes it to another level of "you really need to ROLEPLAY" your character to get what you want out of the game. It's a game where "gaming" the game does not work. There's no magical combination that will let you experience more / be more likely to succeed, you pretty much just have to decide "this is who I want to be" and be that to the best of your ability (and the word ability here is only in reference to how your mind goes about playing the game.)

I haven't played King Arthur but, yes, undoubtly without question, AoD is a challenge and every single choice you make matters, even the seemingly most insignificant dialogue options. In world of RPGs where if you choose the dialogue option "I don't care about that" when someone asks for your help and it equivocates to a neutral decision and doesn't affect the game other than you opting out of the quest; if you say that to someone in AoD who is asking for your help they'll likely be like "well why the fuck did you start talking to me when you can clearly see I'm in the middle of something I need help with?! You're wasting my time and now I don't like you" and any avenue you may have had to interact with them in the future is GONE because you thought it was like any other RPG where you can come back to it at your convenience, but, no, they needed your help NOW, not in 3 days because in 3 days all the fresh-fish on their cart is going to be spoiled, they need help fixing their wheel NOW so they could get out of the sun and save their fish, you dick!

I don't know about that, in my experience the main questlines in AoD are mostly designed well enough that you usually can get out of most dangerous situations and won't get stuck...mostly you're given fair warning about potential dangers if you just use a bit of common sense (e.g. "should I really follow that shady guy I met five minutes ago into some dark alley?").
The challenge is more to see as much of the optional content as possible and get the best results for your character. I did have a few frustrating playthroughs where I got stuck or close to being so (notably Daratan praetor is bad in this regard imo), but that was more of an exception than the rule. One thing is however vitally important: One really has to focus on a few skills, build them up and ignore the rest (and a few skills like Etiquette can pretty much be ignored anyway). One can't play AoD like many other rpgs where it's possible to get pretty much all skills and abilities, one really has to specialize.

Pillars of Eternity