relative speed of incremention syntaxes (or "i=i+1" VS "i+=1")

[woooee]

as the += notation seems to be a syntaxic sugar layer that has to be
converted to i = i + 1 anyway.

That has always been my understanding.  The faster way is to append to
a list as concatenating usually, requires the original string,
accessing an intermediate block of memory, and the memory for the
final string.
x_list.append(value)
to_string = "".join(x_list)