Parmandur
Book-Friend, he/him
Looks like you already got an answer about the math, so as to the other two questions:So I went through the Demiplane free content and unfortunately it seems to have very little about the actual mechanics of the Endeavors. One problem I had trying to do Skill Challenges in 5e (even using Giffyglyph's Darker Dungeons framework) was that between Expertise + the deeply varied skill bonuses + bounded accuracy it was difficult to consistently hit a satisfying easy/normal/hard DC set unlike 4e's perfectly managed by-level tables. How does the guidance to the GM for this game around that, and the actual mechanics work to facilitate Endeavors? I saw some stuff regarding Expertise in the free rules, but that seems like just fictional permissions to know details about the world?
Does a "non combat specialized character" just mean somebody who has put more skill points (?) into abilities without direct combat uses?
Yes, combat and magic are both Skills now, ao characters without a combat focus at all are easily possible.
"Epertise" has nothing to do with 5E Expertise, somewhat annoyingly, but is an "open class" way for a player and DM to more narratively define what a character is good at, more like 2E Proficiencies than 5E Skills. So I can take Expertise in "The Criminal Underworld" and get more chances to roll when I lean into that roleplaying aspect...and these cna be just about anything one wants.