@Ismael04: If your Galaxy S21+ is intended for use in the US, and you are currently outside that region, then this can create compatibility issues with software updates. If you are unable to update to Android 14 via Settings > Software update, and you have access to a home computer, the you can try using Smart Switch to check for any available updates.
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.
