I mainly just wear polos/golf shirts now but when I wore dress shirts Charles Tyrwhitt was my go to. Pretty customizable (button down, wide collar, normal collar, tailored fit, slim, regular, etc) and I liked the fit. They often have really good sales and you could get like 5 shirts for $200 or something. As I said, been a few years so inflation probably upped that some, though.
Have picked up a couple Mizzen and main shirts as I like the material.
I like bonobos for slacks and chinos but their shirts never seemed to fit. Didn't matter the cut it got, it was too tight in the shoulders, chest area. And their service has gone to ***** I did a Black Friday sale order and it took over a month to fulfill. By the time they did the items I really wanted for the order were out of stock and I only got the "filler" items. A business that only does online orders has to be better than that.