>>129215502to keep things short, the Golden Path is a plan by Leto to spread humanity so far and wide in the universe no single event or single person could ever affect all of humanity
thereby ensuring humanity's survival and continuous evolution (biological and cultural) for as long as the universe can sustain life, and possibly even beyond that
the means by which he achieved this wasn't just to present humanity with the technological advances to do so, but also instill a base omnipresent cultural desire to expand in all of mankind
which he did by turning himself into the "ultimate tyrant" (ultimate here being used to signify both the greatest and the last) which ruled all of mankind across the galaxy for 3000 years in such a specific way that when he died, the sheer collective trauma would never quite leave human culture again
an additional part of this is that prescience (future sight) is a thing in the Dune universe, and Leto was by far the most powerful one
But it does come at a cost of locking you into the future you try to determine
Part of what he did was to not just find out the means of making people immune to any form of prescience, but to do so on a genetic level so that after him, prescience would never again be perfect due to the sheer amount of people it can't detect
