Question about removing devices and accounts

Hello.

In my iPhone, I can go to Settings-> Apple ID , scroll down and press one of the logged in devices there, and then press "remove from account", to remove a device or account.

I can also go to Find My to remove a device.

What is the difference between them in terms of effects?

Let's say i have a scenario where someone has a phone and can't remember the passcode and needs to restore the device. After which they can enter their own apple id and password and set up and activate phone.

The device however is in someone else's apple account (family) and needs to be removed from that account first before other person can proceed with the restore. Family members are a distance apart.

How would you remove it from the account? Would you do it from Find My and remove device or would you remove the account in the apple ID section?