I will inform you, but you won't like the answer.
Brooks Brothers. You go in and get sized and get two copies of your measurements. If you are "normal" , then you strike up a repoire with a member of the staff. If you are not "normal", you go semicustom This means that with your measurements, a suit is made up in New York according to a pattern you choose. I happened to have chosen suits with functional button holes and two pair of pants, but no vest. You sit down more than you wear a jacket.
About this time everyone starts with the " I don't need a suit." BS. My brother-in-law came up through the ranks in construction When he became a contractor, he followed my advice and put a suit and shirt and dress shoes in his construction trailer on a coathanger Makes a difference when going to a meeting with a client or submitting a bid, right?
I read that you weren't near anything. You get measured. You keep the measurements. Then, whether you use Brooks Bros or anyone else mail order, you have the measurements.
At this stage, if you don't know, for example, your suit size, arm length, neck size, waist size, shoe size, you had better get busy.