Half of all models/items in large cells won't show up in my Creation Kit's render window, can't mod anymore

[VanyarElf]

Hey everyone, recently upon booting up my Creation Kit I've discovered a problem which seemed to crop up at some point but wasn't present before, which is that every single relatively large cell I try to edit in the Creation Kit, from the base game that is, seems to be missing at least half of all its static objects, items, containers, etc. It's as if my render window developed some kind of rendering quota. 

All of those statics and objects still appear in the cell view list, and if I pull their model from the object window and place it in the cell, it will show up normally with its mesh and texture, but half of the cell's original objects remain completely invisible and unclickable in the render window. For example, here I am booting up the BoS bunker in Hidden Valley, and you can see it only loads up a couple of hallways, while everything else is missing. You can also see that the navmesh for the missing rooms is still there, and the room boundaries too by the way, but the statics and items are not. 

This is completely preventing me from making any mods and I desperately need some help figuring it out. Things I did so far:

Reinstall the creation kit, checked that multiple masters are allowed to load, checked that the statics and objects aren't missing from the game itself ( They aren't, they're only gone in the render window).