Passkey is some sort of specific unique key to a device allowing to use a pin on a device instead of the password. But which won’t work on another device.
Now I don’t know if that key can be stolen or not, or if it’s really more secure or not, as people have really unsecure pins.
Mot likely it won’t need to have chrome. However maybe Google services may be required.
However it is also very likely, if a device cannot support such feature, it will only require a password and 2fa.