Have you tried using the documentation for Pandas to make a toy dataframe and save that as .csv file like df.to_csv('my_csv.csv.') (purposefully no complicated path), and then reopened it?
Can then you use your system’s graphical user interface to move the file you are trying to work with to the same place and see if you can open it just using the file name?
It looks like a typical path problem. From inside Jupyter can you see that file and navigate to it properly using pwd and ls and %cd? (Note you have to use the magic version of cd to change the directory and have it take effect beyond that single line.) Explore using those to navigate your system’s hierarchy from inside Jupyter and see if you can get there. (That advice is in expanded form here if that is unclear.)
Are you using OneDrive? That puts files in places that aren’t always clear to the user.