for the open world aspect of things, the roamer NPCs and scenario NPCs "the ones you see doing stuff like carrying wood and saddles and stuff in town" are all synced host side currently so they don't multiply and same goes for the animals and fishing and random encounters. the issue with the story stuff currently is that there is a ton of scripted stuff in every mission and its way too much to handle and understand every element currently, there really isn't a good source for all the scripting in missions. so temporarily the story missions are not synced at the moment but I'm working on them. but the project is definitely in way better shape than ragecoopv currently because I recently played through gta v with it and sometimes it would desync and have tons of issues if you play the mission the same time. I'm making an announcement trailer for the mod currently so you will see more gameplay on how it works soon and ill post the link here.