Taking on board your bra comments, I have found Bra Stop to have a wider range of back and cup sizes than Bravissimo. I like Flirtelle as a brand, those bras hoick me up more which gives a good separation between boobs and belly, and that reduces the visual blockiness of my torso. I know people are focusing on your bras, which you don't want, but my experience is once I got a bra that properly shifted them away from my stomach, I had a better shape in my clothes.
Clothes wise - what about barrel leg trousers? Not quite as drastic as full wide legged jeans/trousers but give definition, look easy to wear and on trend. I have seen many folk on Instagram talking about them. I think Cos have a pair of maroon barrel leg trousers that are v popular, and they look v wearable. The colour isn't too heavy.
Tops, I know people go on about tucking in tops, but if I do, all I see in the mirror is BOOBS then legs. And I don't want that. I wear tops either fully untucked, or I tuck them in tight, then pull out so I can move. Prefer untuck though.
I loved wearing wrap tops, my old favourites that I still wear are Jojo Maman Bebe pregnancy wrap tops (my youngest is 11) or some i got in GAP a hundred years ago. Unlikely to have any in shop now, but possibly try Vinted if you want something temporary as you change shape.
I also remember a few years ago loads of folk buying a Hush dress that sounds similar to the M&S jersey tie waist dress. Again, Vinted could have some?
Good luck. I've been where you are and found it frustrating.