I think OP means that they used aaa+facebook@smthg.com, so aaa@smthg.com is now revealed to be their main address.

As opposed of having facebook@smthg.com only

I did it like the first one first then moved to the second, where @smthg.com is my domain, but it also has my name in it so it seemed counterintuitive to link my name to it.

ah ok, thanks for the clarification this is a common problem with domains with actual names

Because it has my name in the domain. Since I was doing it for to help with privacy too, it seemed counterintuitive.