I bought a 38L Suit Supply Sienna and 38L Suit Supply Napoli Faux Uni. On both of them the trousers are insanely tight. My usual size is 34 x 32. These are listed as 33, but I figured there was room to let out. I can't button up either pair of trousers, but aside from that the taper is so slim that I look like I'm wearing skinny jeans or tights.
I have a Napoli and didn't have this issue and my pants are not that slim to me. They have slimmer cuts than this. My drop is 42 to 34 though. I think your chest size is cut for little guys for any suit supply suit. You sound relatively tall for a 38. If you have bigger legs than upper body these suits might not be for you.