Impossible to fix vulnerability (giving root) to all iPhones from 4s to X
github.com
github.com
-sideload apps that cant get to the app store, not just for piracy,example :file manager, adblocker, firewall ...
Sure its doable without a jailbreak, but its restricted and require paying apple a yearly $100 developer fee
And some few extra cydia tweaks can be really usefull