Yes, I'm in a similar process with 'flattering', Flo. I haven't quite figured it out yet what exactly is bothering me and why it's bothering me now. It has to be related to whatever's in the air at the moment. It's left me wondering where all these style rules are coming from, some are easier to pinpoint than others and therefore easy to reject on account of their roots but they seem to continually pop up out of nowhere.
I often bring it back to proportions on here, it's where my eye tends to go and what feels aesthetically harmonious to me. I deem it 'safe' as it's tied in with instincts tied to evolution and fertility although my learning of proportions is tied very much outside of the human form and based in nature as a whole Fibonacci, the golden ratio, etc.
But I am left wondering whether this not just an easy out. Is it just misogyny, or women policing women (which I've always experienced as the most stifling when it comes to clothes rules). We seem to be rather insistent on women all looking like an hourglass, the variation seems to be from fuller to slighter and men need to be inverted triangles who just vary in bulk a bit. Reality is both these body types are the rarer sort of the sexes so saying that's natural is becoming a bit of a reach.
I do have an admiration for the Gen Z-ers as they seem less caring about 'flattering'. They're wearing things that I know my generation at that age would recoil in horror over, it would be unthinkable somehow and I'm not sure where that enforced attitude came from and my generation definitely still carries it internally. It was very centred on fat and love handles/muffin tops specifically, when the cut of the clothes was predominantly the cause of it. I like that Gen Z-ers have collectively rejected sexy underwear, in a very short period of time Victoria's Secret went from a mega brand to something rather pathetic and tainted, there's more to it than that, of course, but a large part of that is a lack of an expected consumer base and they are mostly wearing comfy pants with fun designs that please them first.