I’m not inclined to create a unlikable protagonists either. If flawed means unlikable to you (despite the tools in the Lesson), skip it. It’s perfectly valid to write stories where characters are basically good and have no reason to change (or don’t change). Most older stories (Bible, fairy tales, quests) have no character arcs and succeed on their own terms. The same is basically true for many series characters and protagonists in many comedies.
This article is not too bad at describing different kinds of stories, and you might find a match for what you’re looking to achieve. https://www.youtube.com/watch?v=PSXVKnMGjR4
I can help, but not in terms of character arcs. No need to change means no change. No change means no arc. And this course becomes academic for you.
I’m happy to help as I can. There are many good reasons for writing stories without character arcs (though fears of flaws making characters unlikable would not be included in those reasons). I’ve written stories with no arcs. These rely on different storytelling tools.
I mentioned Rose from Titanic in an earlier reply. Most people find her likable, despite her serious flaws. I’m curious. Would you say that she’s not basically good? More flawed than you could imagine your heroine being? Is there a character who, to you, is as basically good as your character is?