Maybe part of this is to re-define your thinking about "frump" (and this is coming from a person who lives in a totally black/white thinking pattern, so huge grains of salt here...) You seem to think that everything that is not "True Una" is frump. If not 100 percent A, then it must be 100 percent B. Is there a range for A-minus or B-plus?
You say you more and more crave comfort. Are you saying that your True Una clothing is uncomfortable but frump clothing is comfortable? So is the discomfort in True Una clothing the sense of physically pinching, hurting, fighting with you, or mentally comforting, as in affirming your notion of yourself? And that comfortable clothing challenges your self-perception and what, makes you feel guilty because you feel physically comfortable in the clothing?
Can you not achieve both physical and mental comfort while still adhering to your own style persona? Or, and I suspect this might be the case because it is the case with me, are you just sort of up for a fight with authority and you relish sort of poking your nose at social norms/conformity, which you define as being frumpish? (Do not hate me......) I, too, kind of hate authority and want to push the limits but I know where the boundaries lie, and you do, too. I kinda wish I didn't have to conform, but well, I also kind of need my job and there are expectations there.
That's my 2 cents. Honestly Una, you could wear an LLBean comfort waist khaki skirt with a turtleneck and tennis shoes, and your personal style would lift this beyond all frumpishness. It's all in the attitude that you bring to the table, and not so much the garments.