Hi PanosEnrik,
Thank you for participating in the Apple Support Communities. We understand your Face ID is not working and you're missing True Tone after the update, and we'd like to assist. Just to confirm, you have iOS version 14.6, correct? If not, we recommend updating to the very latest version.
Have you restarted your iPhone since this issue began, and then tried setting up Face ID again? If the issue continues after doing that, then you may have a hardware issue where you'll want to have a technician properly evaluate your iPhone.
The True Tone issue may be related to a hardware issue as well. You may consider backing up your phone and then restoring to factory settings to see if the issue persists. Essentially, you would want to set the device up as new and test the issue before restoring your backup. If the issue remains with factory settings, then it's likely a hardware issue that would require service.
Restore your iPhone, iPad, or iPod to factory settings
iPhone Repair - Official Apple Support
Take care.