@Sazoua: Further to the above, if you would like to check Smart Switch on a home computer to see if you're able to complete the update in this manner, then please follow the steps below.
To begin with, please follow the link below, and click on 'How Do I Get Smart Switch On My PC or Mac' to download the relevant version
https://www.samsung.com/uk/support/mobile-devices/how-do-i-backup-my-smartphone-to-my-pc-or-mac/
Once installed, open Smart Switch, connect your S21 using the USB cable that came packaged with the device, and look for an update prompt on the landing page, next to your device details.
