It keeps changing, the quick access is somehow different from the explorer quick access locations, the browse button opens a dialog in a completely different location, the recent menu locations sometimes just doesn't do anything if you click on it, only uses 1/3rd of the screen on wide screens, quick access doesn't seem to be user modifiable, "Add place" doesn't let you add anything except the onedrive that is already added, the clickable buttons are sprinkled all over the place and not clearly identifiable as clickable, sometimes the header shows you paths or sometimes just the name of the current folder, Add to favorites doesn't add to quick access but rather to favorites that is somehow a submenu of recents?!?, favorite locations in excel and word are not syncd between each other, the save as dialog has slightly different buttons available depending on how you opened the dialog, some buttons do something different if you double click them vs single click. It's just raw chaos throughout.
I assume they threw their UX guy out the window and designed this in 5 committees that were prohibited from communicating with each other. It's the only explanation that makes sense