Can't reset my Macbook Pro (2020) to factory settings

I just updated my Mac Book Pro (2020) to Ventura 13.0. Now I want to reset it to factory settings before selling it, but it doesn't work.

I have followed this procedure (Computer and support language is Norwegian. So there's some guess work on the translations):

System Settings -> General -> Transfer or reset -> Erase all content and settings ->

I get a pop up message saying: "Turn on Full Security in Secure Boot. Secure boot must be set to Full security before you can delete all content and settings. Find out more at: About Startup Security Utility on a Mac with the Apple T2 Security Chip - Apple Support " ->

Then I follow the instructions:

Turn off computer -> Turn it on and hitting cmd+R when seeing apple logo -> I get a menu where I can choose between four options: Time Machine, Reinstall macOS Ventura, Safari and Disk Tools.

None of them are getting me closer to turning on 'Full Security'. I now assume that there are requirements I have to meet before going back to factory settings, and these requirements are impossible to meet.

I need help with either 1) turning on full security, or 2) bypassing the whole thing and setting my macbook to factory settings with a different process.

Either way, I just want to sell this macbook. The faster the process and the fewer the steps, the better for me.