Ran into this issue right after migrating the Simple Shooter assets into my project.
When trying to “Build All Levels” it crashes the editor with the error Assertion failed: StreamingTextures.Num() == StreamingTextureGuids.Num().
Looking this error up brought me to this solution UE5 Crash on building streaming texture - #8 by davisctools - World Creation - Unreal Engine Forums where someone was nice enough to create a plugin to fix this specific issue. Seems to be an issue related to migrating from earlier UE versions to 5.0 where asset GUID’s are either duplicated or blank. This plugin specifically https://github.com/davisctools/UnrealGuidFixer needs to be cloned (or you can click on the Code → Download Zip button). Put that in your projects Plugins/ directory. So it should end up looking like this Plugins/UnrealGuidFixer/GuidFixer.uplugin if the GuidFixer.uplugin is in the right spot then you exported it correctly.
Load up your project and make sure you compile. You should now see some extra options under the Tools tab. Fix Material GUIDs, Fix Texture GUIDs, and Fix Empty Texture GUIDs. I ran them all but it seems like only the texture and empty texture fixes were needed. After each one is run go to File -> Save All. You can run them multiple times just to double check it fixed everything.
Once that’s all done running “Build All Levels” will run correctly without crashing.
Hopefully this helps for anyone else that runs into this issue.