I have an iPhone 13 Mini. When I attempted to run an app I was developing on my phone, I found that the Settings > Privacy & Security > Developer Mode was missing. I realized that I was still associated with a defunct app developer team from several years ago. So I left the team (https://developer.apple.com/help/account/manage-your-team/leave-a-team/), updated my developer account, and then rebooted several times but Developer Mode was still not showing up. I began to think that joining the fee-based Apple Developer Program might be required. I checked back yesterday (after ~4 days had elapsed) and noticed that the Developer Mode option was available (even though I had NOT joined the fee-based Apple Developer Program). So for anyone reading this, allow for system latency after leaving a team and/or updating your account.