You should almost certainly go to a tailor. It makes a world of difference if "professional" is your goal. It can be tricky to find a good one, but when you do, it's incredible. It can be surprisingly cheap too (although building a wardrobe that has high quality piece that are worth tailoring can be quite expensive. This is best done gradually)

I think that this is especially true if you're on the larger side, because a greater amount of body mass means that qualitative differences in where we store that mass will be more apparent.

Something I liked about going to a tailor is I could show them clothes that I liked versus ones I didn't (or explain what had been bothering me about certain clothes). They were able to suggest alternatives.