The privileged extension does not require root.

You _can_ install it with Magisk (which also provides root) but it can also be flashed as a regular flashable ZIP (which just requires an unlocked device).

Last (and best) of all, it can be added to an unrooted ROM. RattlesnakeOS[0] for example includes it.

[0]: https://github.com/dan-v/rattlesnakeos-stack

Not necessarilly. One can enjoy Privileged Extension on an unrooted phone by using a custom ROM, LOS for example.

edit: typo