I think this is a valid spectrum through which to view fic and for some canons I view it this way and have the same tastes as you. For example, when I was in Star Wars fandom, I never wanted any setting AUs at all and would have stayed in the A to C range.
In terms of wangxian, though, I do find a lot of value to be found for me even in mundane AUs simply because the relationship dynamics between wangxian are rich enough that they can transcend the setting entirely while still feeling like they have something to say about wangxian as individuals and as a couple. They're also such an archetypal sunshine/grumpy ship to me that they slot in well in many different types of AUs. So for them, in terms of reading, I have no real preference for canon compliant vs canon divergent vs setting AUs/mundane AUs except to say I actually really don't like it when it's a setting AU, but the plot beats are the same as canon. I find those rather boring and wonder why bother with a setting change at all in those circumstances.
In terms of writing though, when I approach fic, I'm not necessarily looking to replicate/exactly reflect canon or give myself more of something that precisely reminds me as canon. I see writing as a conversation I can have with canon or a way to tease out pieces of canon I want to explore in ways that are impossible if I constrain myself to writing a canon-observant story. The theme I want to play with will usually dictate everything else about the story and from there I'll take what I know of the canon characters and try to make it in-character for how they'd react in that new situation/setting. It wouldn't work to write origfic for these mundane ideas though because the themes I want to play with are usually tied pretty tightly to canon characterizations, relationship beats, or plot elements and removing it from canon is easier than having to write around canon events. It's a conversation with the canon, even when the setting is so far removed.
I will say, for myself, I know when a fandom is one where I'll branch out into D-E fic territory and it's entirely dependent on how dynamic I find the ship to be. If they are completely compelling to me, I'll usually have an easy time of enjoying it. If I like the ship because of the plot circumstances/their canon jobs/whatever, then I have a harder time venturing out. With wangxian, I see their story and dynamic playing out in any setting. I love those characters so much that I want to explore or read about every possible facet. A lot of ships for me don't hold up when they're placed into different scenarios because they need the scaffolding of canon.
no subject
In terms of wangxian, though, I do find a lot of value to be found for me even in mundane AUs simply because the relationship dynamics between wangxian are rich enough that they can transcend the setting entirely while still feeling like they have something to say about wangxian as individuals and as a couple. They're also such an archetypal sunshine/grumpy ship to me that they slot in well in many different types of AUs. So for them, in terms of reading, I have no real preference for canon compliant vs canon divergent vs setting AUs/mundane AUs except to say I actually really don't like it when it's a setting AU, but the plot beats are the same as canon. I find those rather boring and wonder why bother with a setting change at all in those circumstances.
In terms of writing though, when I approach fic, I'm not necessarily looking to replicate/exactly reflect canon or give myself more of something that precisely reminds me as canon. I see writing as a conversation I can have with canon or a way to tease out pieces of canon I want to explore in ways that are impossible if I constrain myself to writing a canon-observant story. The theme I want to play with will usually dictate everything else about the story and from there I'll take what I know of the canon characters and try to make it in-character for how they'd react in that new situation/setting. It wouldn't work to write origfic for these mundane ideas though because the themes I want to play with are usually tied pretty tightly to canon characterizations, relationship beats, or plot elements and removing it from canon is easier than having to write around canon events. It's a conversation with the canon, even when the setting is so far removed.
I will say, for myself, I know when a fandom is one where I'll branch out into D-E fic territory and it's entirely dependent on how dynamic I find the ship to be. If they are completely compelling to me, I'll usually have an easy time of enjoying it. If I like the ship because of the plot circumstances/their canon jobs/whatever, then I have a harder time venturing out. With wangxian, I see their story and dynamic playing out in any setting. I love those characters so much that I want to explore or read about every possible facet. A lot of ships for me don't hold up when they're placed into different scenarios because they need the scaffolding of canon.