One thing you could check is how you have your nemo (default) file manager set to display items. I find that by setting options for display other than default can cause my desktop to become quirky.
The desktop display is only a glorified folder after all.
Yeah- i haven’t changed any defaults in nemo- The icons on the desktop are full opacity, it’s just that any window I bring up goes transparent- not sure hwat is triggering it- I suspect it’s the ‘peek’ feature where you have a window open and want to see desktop without actually minimizing the open window- just hover the mouse over a taskbar- and it will ‘peek at the desktop’ by making the open window transparent’
If it is that=- i have no idea how to fix it- or where the peek feature is even located