There is no official stockROM Aandroid 10 for the S8 SM-G950F.
That would have been the next step. ;-/
In your case I don’t see any need. Whether stockROM Android 9 G950FXXS6DSL2 with December 2019 Security Update or stockROM Android 9 with March 2020 Security Update is not important here.
With my S8, that wasn’t necessary.