Cannot reduce security when booting from external SDD, "no administrator is found"

I've read other posts here but my issue is nuanced. My computer was accidentally wiped by Find My. I want to try a tool to see if any data is recoverable. In order to use the tool I must reduce security for third party. I am able to boot the Macbook Pro M3 from an external SDD with Sonoma. There is an admin user created. When I get to the screen to select reduced security I get a "no administrator is found error". I tried creating a second admin user, making sure to have a full name in the description. None of the other fixes worked. I realized after many attempts and finding the article linked below that I wasn't given the screen to select and log in as administrator. These instructions: https://support.apple.com/guide/mac-help/change-security-settings-startup-disk-a-mac-mchl768f7291/15.0/mac/15.0 "Step 5. Select an administrator account, then click Next." That screen to select administrator flashes and goes away before I can do anything. So that's why I'm getting the error no administrator because I cannot select and use the administrator account on the bootable SDD. I don't want to install new OS on the Mac before knowing if there is data to recover. Is there a way to get admin user recognized by the system booting from an external drive so I can reduce security?