How can I add another trusted root CA cert to my iPhone SE?

I have been trying to get this working all morning and I think there has been a change somewhere in iOS 16. I followed the steps from multiple sites, such as Trust manually installed certificate profiles in iOS and iPadOS - Apple Support, and everything seems to work up until I get to the "Certificate Trust Settings". The profile (CA Cert) itself is installed, but the only options I get are "Trust Store Version" and "Trust Asset Version". There is no option to "Enable full trust for root certificates". Is there a setting somewhere, like a security setting, that I need to enable for it to show up?

This is entirely for personal use, so I would rather not go through the effort of setting up and maintaining Apple Configurator or MDM to install the profile. I am currently running on 16.6.1 and below is a screenshot.

1. Is this your corporate iPhone? Then please contact the system administrator of your corporate
2. If it is your personal device, in that case, do you have any profile installed by your corporate/organisation/enterprise/School Management?
   1. Erase the profile added by you If you have installed a profile on your own --> Install or remove configuration profiles on iPhone - Apple ...
   2. Or please contact the system administrator of the organisation who provided the profile to you
3. If you want to turn on SSL trust for that certificate, go to Settings > General > About > Certificate Trust Settings. Under "Enable full trust for root certificates," turn on trust for the certificate. Apple recommends deploying certificates via Apple Configurator or Mobile Device Management (MDM). --> Trust manually installed certificate profiles in iOS and iPadOS ...