Anchor for insulated double plasterboard
These toggler anchors will work for thin to very thick walls.
You do not say what the insulation is, The insulation may be a factor in getting them to toggle into place properly. I sometimes use a wire to push fiberglall insulation aside a little so they sit properly.
I have posted several answers about installing these anchors read a few for info and tip/tricks.
https://diy.stackexchange.com/search?q=user%3A56737+toggler