The act of rooting a device is essentially just giving you access to the highest user permissions, that being equivalent to the “root” user on a Linux system.
This means you get full access to the filesystem and any commands, even if they’re usually reserved to the system.
Rooting is only the act of gaining this access. There is also Custom ROMs - Custom versions of android which cater to various audiences. Most notably there’s projects like LineageOS which aims to provide a polished android distribution that works on many devices.
There’s dedicated communities around specific devices, most notably on the XDA Developers forums and Telegram.
Note that ADB is intended for app development, and whilst it does give you more permissions, it isn’t on the same level as a full root solution like Magisk.
(If you wanna follow-up privately: @tg_rush:matrix.org)