Your problem is likely EPO. That mod is flat out broken as is the Redux version. I spent ages trying to track down a random CTD problem in my game and it turned out to be that. if EPO.esp is Extreme Particles Overhaul anyway. I think the mod has a bad mesh or texture in it that causes it. As for the state of your save you should download https://www.nexusmods.com/fallout4/mods/22633 and have a look at your save file in there. look for Suspended stacks and how many active scripts you have. if there are suspended stacks it means the script engine has bin overloaded and terminated a bunch of scripts. if this happens your game can become very unstable. if you have a large number of active scripts it could mean something is stuck.