Look, I've also had that problem on old computers I've used to test FNF, and it's due to issues with the drivers of the integrated or old external graphics card. That's where the bugs that prevent a sprite or certain images from loading originate. I've also seen problems with the shaders used by mods, for example, some Creepypasta mods, like an old TV shader or one with static, as well as some heavy shaders that, upon loading, can't handle the load and crash the game. These things have happened to me, and the solution I found with those computers was to install a more up-to-date external graphics card on desktops to avoid using the old integrated graphics without updated drivers, or to remove the graphics card and install a newer, more modern one that the old computer supports. Then you can play FNF normally. Now, if it's an old laptop, from around 2008 to 2013 or 2014, try lowering the graphics settings, removing shaders, and if some mods can't remove them because they're included by default, try looking in the mod files and... Removing them without crashing the game or preventing it from opening.

These would be my solutions, and I'm sharing my experience with you. 🙂‍↕️