I tried to activate Siri but I can’t even find anything related to click on

You should find Siri in Settings>Siri & Search. You can turn it on there and make additional settings there as well. You may wish to check here, iOS - Feature Availability - Apple and make sure Siri is available in your location.

You're welcome. There won't be a Siri icon in Screen Time, that is where you check to see if you have an Restrictions turned on. That is what I said to check there for. What troubleshooting have you tried? Check this for some troubleshooting tips, If Siri or "Hey Siri" isn't working - Apple Support

If you checked the link that I provided and Siri should be available in your location, the next step would be to see if you have any restrictions turned on that would disable Siri. Go to Settings>Screen Time to check for Restrictions.

Yes, go ahead and make a Genius Bar appointment at the nearest Apple Store to have it examined by Apple.