I find Next frumpy. It's terrible quality and compared to how it was in the 1980s it's rubbish.
I think it's on a par with the worst of M&S to be honest.
OP I think you need to find your style then find the stores not the other way round.
I spend a lot of time in smart casual trousers, so I invest in those and good knitwear - cashmere and wool- with a fashionable twist- The White Company (sales), Jigsaw, Boden, Whistles.
I'm prepared to pay as I know I'll get years out of it.
My other winter staple is knitted dresses with boots and cardis- as above.
Then I add jewellery, scarves, hats, boots etc.
I like a minimalist look in neutral shades- black, grey, camel, navy, blues and some pinks.
I think once you know what suits you, you will find it in the shops. Stop thinking you have to 'go to a shop' but look at everything on the high st and online.