That would be set nostartofline
. With it, gg and G will keep the column if possible just like j etc.
From :h startofline
:
'startofline' 'sol' 'nostartofline' 'nosol'
'startofline' 'sol' boolean (default on)
global
{not in Vi}
When "on" the commands listed below move the cursor to the first
non-blank of the line. When off the cursor is kept in the same column
(if possible). This applies to the commands: CTRL-D, CTRL-U, CTRL-B,
CTRL-F, "G", "H", "M", "L", gg, and to the commands "d", "<<" and ">>"
with a linewise operator, with "%" with a count and to buffer changing
commands (CTRL-^, :bnext, :bNext, etc.). [..]