The classic Railroad is clumsy, it's just the DM doing and saying whatever they want to happen. So no matter what the player do the DM just says "nope". The DM does not even bother with 'rules', things just happen.
The metagame one is where the DM uses their "inside knowledge" to stack the game against the players, all by using the rules. This can fool at least half of the players as they will say "wow, amazing the foe had a Potion of Escape".
The last one is Hard Fun. The DM uses their skills, intelligence, game mastery, rules mastery, life mastery and such to simply out do the players. So the DM makes tough powerful NPCs or sets up hard game realities for the players.
Of course most bad players ignore all the above and just say "If I don't like it it's a Railroad!"
I still don't understand what the difference is. You are still making whatever you want happen. You're just giving longer explanations for why the thing you want to happen was always going to happen.
So you described what I call the random mess.
To move a plot or story forward in a meaningful way, events have to happen or not happen. You can't just have a random mess on top of a random mess. My way, and I think the best way, is for the DM to use Force to make things happen or not happen. Then I know of the scripted and Improv Quantum way......but what else is there?
This is why I gave the easy example: How to do a reacquiring villain? So, once Force is off the table, what else can a DM do?
You frame a new situation that includes that villain again, assuming it makes sense that they can. (E.g., if the players personally decapitated a particular villain and then ritually burned their corpse so nothing short of
true resurrection could bring them back, they're probably not coming back.)
Like, let me give you an example literally playing out currently. Right now, I only have two active players, and one of them needs to take time off for medical reasons on the regular. So I sometimes run solo sessions for the other player. TL;DR: The character was a purely non-magic Warlord-type (a Captain in the Royal Army of Al-Rakkah) for a long time, but due to a choice he made a while back, he's gained powers related to spirits and the remnants of dead souls. He's being guided in how to learn to use these powers by the leader of the "good" faction of an assassin cult (too complex to explain, just run with it), and his guide had seen signs of a spirit-presence he could gain further beneficial (rather than purely violent) powers from.
This gave me the opportunity to bring back in a villainous organization that had, previously, been
pretty thoroughly slapped down not once but
twice by the PCs: the Shadow Druids, a secretive organization of death-obsessed druids who want to turn the PCs' arid homeland into a death-filled swamp so they can be all-powerful within its bounds and "live" forever outside the cycle of life and death. The first time, the PCs destroyed the Shadow Druids' local cells, pretty thoroughly breaking their operation in the main city of the area. The second time, they stormed two different main base areas--one caught by surprise and levelled, the other swept clean after the baddies had managed to get away. But being down two bases
and having all their local operations scoured clean? Yeah, that was a
huge blow, and for most of the past 3-4 years of IRL play, the Shadow Druids have been a non-entity.
But the thing is? They
learn. After the first run, they learned to start impersonating actual people with their shapeshifting magic, something regular druids can't normally do. (They can shapeshift into a
generic creature's form, not a
specific creature's form.) After the second run, they've learned they need to operate by the rules of the city if they want to conquer the city--hide in shadows, never be seen, leave no paper trail, hunt targets that can't fight back or that won't be missed, strike with overwhelming force against targets that might cry out, etc.
So I framed a new conflict (in Dungeon World terms, I put together a new "Front") that fits with this idea: the Shadow Druids have started recruiting
outside of just druids, something they've never done before. The Captain has thus been investigating, using a mix of his intelligence, strategic thinking, and spirit-powers to track down this "Dark Hunter" the Shadow Druids have recruited to their cause. He's slowly piecing together the Dark Hunter's diabolical plan, and really doesn't like what he's seeing--at present, it looks like she is gearing up for eventual
war, using unwitting Nomad Tribesmen as footsoldiers led by Shadow Druid commanders, and intending to soften up the city for possible invasion.
I didn't need to
force anything. I provided scenes that the player could interact with, and he sought out knowledge in ways befitting the character's personality, skills, and powers. As he does, he uncovers the danger that lies in wait. If he achieves highest success, he may nip this problem in the bud. If he struggles, it could grow into a serious problem. If he stumbles badly....it could be war. Many possible outcomes, all of which depend on the specific path he and I chart out together. Certainly, if the Captain does nothing, Al-Rakkah will suffer a cruel fate. But it is both the trial and the triumph of the adventurer to see that a cruel fate befalls only those who deserve it.
Yea, I'd just tell such players to stay home and write their novel.
But that's exactly what is going on above. There is a bad situation. If nothing changes, it
will get worse. Fortunately, the players are sources of change. Unfortunately, that change may not always be good--but fortunately, whatever change results, we'll have fun discovering what it will be.
We play to find out what happens.
All of us. That doesn't mean I don't know what the world is, nor that I have no preparation done. Far from it. I have a timeline, and lore, and multiple factions all pursuing their devious ends, and plots the players don't know are playing out right under their noses. But it does mean that I, personally, do not know exactly what the conclusion will be until it happens. Because the players are the ones making that happen, not me.