In case this is helpful to you:
There's a back button, which if you just went into a child folder from a parent folder, then pressing the back button will go to the parent folder.
If you explicitly want to go to the parent folder, clicking on the name of the current folder in the dropdown in the top center of the open dialog, will reveal a list of folders that is the hierarchy from current folder on top, to root folder on bottom.
You can also press Command + Up Arrow to go to the parent folder.
To edit the path as text, press Shift + Command + G, which will show a dialog with the current path, and allow you to edit it as text with autocomplete support.
Bonus tip: While in the file open dialog, if for some reason you want open the current directory in a full normal Finder window, press Command + R.
There's a back button, which if you just went into a child folder from a parent folder, then pressing the back button will go to the parent folder.
If you explicitly want to go to the parent folder, clicking on the name of the current folder in the dropdown in the top center of the open dialog, will reveal a list of folders that is the hierarchy from current folder on top, to root folder on bottom.
You can also press Command + Up Arrow to go to the parent folder.
To edit the path as text, press Shift + Command + G, which will show a dialog with the current path, and allow you to edit it as text with autocomplete support.
Bonus tip: While in the file open dialog, if for some reason you want open the current directory in a full normal Finder window, press Command + R.