BINGO! But they are easy to replace and have some effect hence their popularity.Buffers and springs are bandaids and snake oil.
Once an adjustable gas block is set you don't fuck with it (unless you swap back and forth between shooting with or without a suppressor).Adjustable gas blocks are an unnecessary failure point at one of the most critical points of keeping it a semi-automatic rifle.
The gas port on the (non-adjustable) MicroMOA Baby Govnah gas block ($30) can be easily drilled to whatever diameter works best on a rifle but it takes a little time and effort. It requires a cordless hand drill, a set of bits, and a little trial and error and can be accomplished on the shooting bench at the range.
I haven't found one that really works.If you want it to shoot flatter, screw on a comp/brake.