‘Natural’ fusion will only get you as far as iron. Supernovae may produce heavier elements, but the heaviest elements like gold are probably produced in neutron star collisions.
Supernova explosions are good enough to make gold (and most other heavier elements until plutonium) by neutron capture.
Fusion, as you say, produces quantities that diminish very quickly for the elements beyond iron (iron 56 has the greatest binding energy of any nucleus and the binding energy decreases slowly after it), so that the last element that is produced in non-negligible quantities by fusion is likely to be germanium.
Fusion, as you say, produces quantities that diminish very quickly for the elements beyond iron (iron 56 has the greatest binding energy of any nucleus and the binding energy decreases slowly after it), so that the last element that is produced in non-negligible quantities by fusion is likely to be germanium.