Sydney page options missing

hi, I lost the “Sydney page options” menu on the page editor. I tried toggling it in the settings/preferences but to no avail.

I need it to set the transparancy behaviour of the page header. Is there any way to get it back?

I tried reinstalling the theme, but that did not work, and the page code only shows the blocks, not the sydney settings (as far as I could see)

help appreciated!