Why doesn't any space clear up after I delete an app from my iphone?

It doesn't matter what software version or app I have because it just makes sense that if an app takes up 4.3 MB, when you delete it and restart your phone 4.3 MB should be available.

You have to factory reset your phone. I know it sucks. Backup your pictures on a cloud. All your apps will come back up after the factory reset. For some reason not everything can be deleted.

Factory reset is not necessary. Some iPhone Space Saver like iMyfone Space Saver for iPhone may help, as far as I know their new versions will include "unuseful apps removal" to free up space.