Re-opening project completely changes project textures

Hello,
I’m very new to UE4 and I’m attempting to get into it to create 3d video game edits. I’ve run into a problem when I re-open my project, the project is almost completely different. I’ve saved everything, all objects, animations, etc. and these are all saved correctly, however re-opening UE4 changes the look of all these objects. I haven’t messed with any settings and have used all default settings. I’ve been able to render fine whenever I’ve started a new project from scratch, with all objects working perfectly. If I re-open the project, setting each texture as two-sided in the editor and then undoing that and clicking apply fixes the texture. However that doesn’t help much since there are too many textures in each model to do this every time I open UE4, plus the lighting and reflections are still lit. I’ve tried resetting my shaders and that doesn’t help either. Furthermore, the quality seems to decrease quite a bit. There is no anti-aliasing, and the overall texture quality seems lowered. I’ve attached a few screenshots to show the before and after effect when I re-open a project. This also happens with different models and default assets. Hopefully, someone can explain why this is happening so I can fix it!

First time open:

https://forums.unrealengine.com/filedata/fetch?photoid=1772762

https://forums.unrealengine.com/filedata/fetch?photoid=1772763

When re-opening:

https://forums.unrealengine.com/filedata/fetch?photoid=1772764

https://forums.unrealengine.com/filedata/fetch?photoid=1772765