After years of hating button front shirts (gaping, fit issues through the shoulders, etc.) I have found a couple of brands that fit and it's like the heavens opened and I heard angels sing.
I love having back of my neck covered, and do not care to expose my upper chest (decolletage). Collars help give definition to a softening jawline, cover an aging neck, and showcase a pretty (vintage) scarf/neckerchief or a necklace. Crisp and structured, they play nice with colored jeans/chinos, and with a long cardigan and full tuck (with belt), give the illusion of a waist (MIA since 2005.)
My go-to brands are Duluth Trading (their wrinkle free shirts have hidden "bust proof buttons" to prevent the gape) and Orvis (I size up and their cut is streamlined enough that it doesn't blouse up with extra fabric.)
In the summer I wear no-iron L.L. Bean tunic blouses (men's wear type stripes) and they provide coverage of all of the above PLUS I don't tuck, so they're super comfy. (I do have slim legs, so tunics work well for me.)
I also wear a thin, short sleeve tee shirt (like a liner - not to be seen) under my button fronts. Not only does the liner provide coverage in case there is gaping, it also protect from perspiration and deoderant/anti-perspirant stains. I've found Uniqlo Heat teach (men's v-neck in a soft beige color) to be invaluable in the winter and I'm looking forward to trying the men's Airism for summer wear.
As you can tell, I'm pretty solid on the value of a button front shirt - the softness and fluidness of knits on my body at my age does not make me happy. So odd to say that because I used to love knits . . . as far as fashion goes, I see them as the classics that suit my style and my body today. If you can find the unicorn that fits you and makes you feel like yourself - whatever those descriptors are - I think it will never go out of style.