What exactly is impossible? I can run any software I want on my iPad. No need to jailbreak. Just get Xcode and enjoy the freedom. Who said I need to upload it

What exactly is impossible? I can run any software I want on my iPad. No need to jailbreak. Just get Xcode and enjoy the freedom. Who said I need to upload it to the App Store? (as a side note, these prohibitions seem to have been relaxed in recent years)