I think the fact that westmarshes traditionally didn't have an overarching plot would help a lot. It was pretty much we know there is a kobold nest over there, wipe it out, maybe get a clue to another dungeon, and that could lead to the next adventure.
I think your plan could work, but you either need to keep track of people's timelines, or always keep the clock running. You cannot stop Jim from robbing the bank, but you could point the police his way. It would also probably be optimal to have some kind of group backing the PC's preventing them from getting into PVP.
Remember too, west marshes is literally, you are all heros exploring the Eastern wilds. The only real base you have is the town and the adventurers guild. You come back and report things you learn to update the guild so others can try and get a group together and explore.
Feel like I am rambling now, stupid mornings. Good luck, I think there is much to be gained from doing a tech marshes universe, but I think the biggest thing is to keep accurate time records 😂.