iPhone 12 Mini - Secondary Unlock Passcode/Password for Safe Mode Diagnostics?

Hi. For iPhones (any model; mine is a 12 Mini), is there any way to setup a secondary passcode for diagnostics testing?

What I mean is, I am having my phone repaired. But the technician is asking for my passcode in order to run testing on mics, cameras, sensors, etc once the new parts are in. It seems reasonable and like good service for them to want to test these components (many of them will be removed and then replaced during repair), however the relinquishment of my passcode is a security risk. It would be wonderful if there was a setting where they can test all of those features without using my passcode. Maybe a secondary passcode that boots into Safe Mode or something like that.

Does such a feature already exist?

Also, although I am in need of this feature for the purposes of repair, I do imagine that there are other reasons why this feature would be useful.