etoken / emtoken is a partition called steady.bin which is digitally signed by daseul which has the key of the rpmb and allows to remove the security that restricts the flashing of a combination firmware on Samsung new model
as now it is rare to get as it is costly in the gsm world , if you are asking to unlock your Samsung device, there are new method.
last year magma tool has integrated new features to enable you flash token with credit, E-Token can be flashed on highest Android 10 model devices. If you have an Android 11 device, and the U version of your device also supports downgrade, you need to downgrade to Android 10. If there is no firmware below Android 11, the device is compatible with your Binary, there is no solution for E-Token for now