Str / Dex depens on ur weapon type
All different weapons have different ratio on how much dmg you will get from either strength or dexterity
But as a fighter, you cant really use anything that requires only dex (except for spear)
So str is the safest stat to use here, because all other weapon bases need str to get most dmg out of it.
________________
Longsword would be the biggest hits, but it's unreliable.
Longsword is a heavy item meaning u can only attack 1 time per 2 second, while regular items will hit 1 time per 1sec, so 2hits in the same time as the heavy do one hit.