If the note 9 has wireless charging coil do you still need to apply the metal thing on the back to use it on magnetic auto wireless charger?

[Mechenzo2020]

I've seen some youtube videos where a note 8 stick to the auto wireless magnetic charger without a magnetic case or a metal ring on the back of the phone.Does note 9 has that and all the phones with wireless charging can do that or only specific samsung phones?Theres another video saying that about s6-7-8-9.Aaand it looked preety sturdy

https://youtu.be/eCUMXQV_iM8

 

https://youtu.be/X4chsx9aesY

https://youtu.be/5sDdVBK5uC0

All the info that ive found is pretty slim and mostly in passing

[RedDeath_]

Any phone will "stick" to the surface if the magnets are strong enough.

[Mechenzo2020]

Allright,makes sense thanks a lot