Here are my results (Galaxy S9+, Android 10, no modifications):
SAF Create 65,7
SAF Open 12,2
SAF Delete 31,8
C++ Create 0,8
C++ Open 0,2
C++ Delete 0,4
I ran each test 10x, then calculated the average in an Excel spreadsheet. The SAF results were also extremely inconsistent (from 56 to 88, even after I had deleted one 126ms result as random spike). I’ll send you those results via email.