Until now, when we wanted to restore an iPhone by reinstalling iOS from scratch and deleting all its content, we have needed a computer, either Windows + iTunes, or a Mac. This could change soon with the arrival of iOS 13.4 because they have been found in your Test version mentions and graphics of a new functionality called OS Recovery, or system recovery, which would theoretically allow you to reinstall everything without using a computer.
This is another step in eliminating the use of a computer that Apple has been carrying out for several years. iTunes is already totally unnecessary for the vast majority of operations that we need to do with iPhone or iPad, although it is still available on Windows and its functionalities integrated into Finder in macOS Catalina. In this way we can still make local backups, encrypted or not, in addition to making our copies in the iCloud cloud, if you have enough available space. However, this possibility is nothing more than an option now, and is practically not mandatory as before.
With a recovery system of the operating system that uses the Wi-Fi radio of the iPhone or iPad, we can totally eliminate the need for a computer, even if we have to go through the bad drink of reinstalling everything. Many iPhone users, in fact, do not even have a computer, so this is a step that Apple has to take sooner or later. The Apple Watch already has its own wireless system recovery system.