[General Questions and Answers] Samiullah Ridoy:
In this post, I'm not telling any tricks or methods. I am just providing my thoughts and possibilities. Recently I was trying to root my phone and I did a little bit of research on it. By the way, note one thing here that my phone is part of the Android One project and made by Xiaomi, so it's much harder to root than any other phone. If you have also tried to root your phone, then you might have also heard these words... (Magisk manager, Superuser, Busybox, SU Binary, TWRP Custom recovery, root file, System file, Custom Rom), etc. In this thread, if I am right you can root your phone just by using ADB Shell. Rooting your phone means...

Rooting (Android)

From Wikipedia, the free encyclopedia

Rooting is the process of allowing users of smartphones, tablets, and other devices running the Android mobile operating system to attain privileged control (known as root access) over various Android subsystems. As Android uses the Linux kernel, rooting an Android device gives similar access to administrative (superuser) permissions as on Linux or any other Unix-like operating system such as FreeBSD or macOS.

Rooting is often performed with the goal of overcoming limitations that carriers and hardware manufacturers put on some devices. Thus, rooting gives the ability (or permission) to alter or replace system applications and settings, run specialized applications ("apps") that require administrator-level permissions, or perform other operations that are otherwise inaccessible to a normal Android user. On Android, rooting can also facilitate the complete removal and replacement of the device's operating system, usually with a more recent release of its current operating system.

Root access is sometimes compared to jailbreaking devices running the Apple iOS operating system. However, these are different concepts: Jailbreaking is the bypass of several types of Apple prohibitions for the end-user, including modifying the operating system (enforced by a "locked bootloader"), installing non-officially approved (not available on the App Store) applications via sideloading, and granting the user elevated administration-level privileges (rooting). Many vendors such as HTC, Sony, LG, Asus, and Google explicitly provide the ability to unlock devices and even replace the operating system entirely. Similarly, the ability to sideload applications is typically permissible on Android devices without root permissions. Thus, it is primarily the third aspect of iOS jailbreaking (giving users administrative privileges) that most directly correlates to Android rooting.

Rooting is distinct from SIM unlocking and bootloader unlocking. The former allows removing the SIM lock on a phone, while the latter allows rewriting the phone's boot partition (for example, to install or replace the operating system).

Source: Wikipedia

So, as much as I've noticed (I could be wrong) mainly all rooting processes does one of those two things,

1. Edits your boot.img

or

2. Adds a SU binary file to your system & more specifically to your system/bin file.

So if that's true and every Android phone or at least the same brands or same models or at least same Android versions or maybe all of them requires the exact same SU binary file(Superuser binary file). Now, if you don't want to change your boot.img there is only one is remaining and that is adding the SU binary file. Now you might ask how to do that...

Just use your ADB shell to give writing system files permission to your file manager. And then put the SU file to your system.

So, that's all I was just trying to say. Now if I am right please let me know and thanks for reading until now. And also if I am right, please someone provide me the SU binary file of Xiaomi MI A3, code name: laurel_sprout . Thank you once again, All developers, take care of your health. For further inquiries and helping me out, message me on XDA personally.

Writer: Samiullah Ridoy.