No offense but you make this sound more like a "powerscaling" issue than a "Death Battle" issue. Which would make YOU the tourist here. Since yes, plot wise, Saitama should win.
But as Death Battle as said before, plot distinctions only matter in their own worlds. Death Battle has to compare the two characters directly; and when done so, Goku just scales way higher than anything seen in One Punch Man.
And this applies to general powerscaling, assuming Saitama can win any VS matchup because he "always wins in one punch" is a no limit fallacy that his own series doesn't even apply most of the time since characters have tanked Saitama's punches before.
I've been getting into animation over the past year! Here's some fight practice I've been working on. Deltarune tomorrow and stuff.
#DEATHBATTLE#kingdomhearts#deltarune