Cannot trust self signed certificate on iOS 15.1

Hello,

I am trying to install and trust a self signed root CA certificate on my device to access services hosted on my internal network.

Importing and installing the certificate went well.

I however do not have the option available to fully trust the certificate.

I have the exact same issue than this one : https://discussions.apple.com/thread/253175842

No answer has been provided to this post, other than to switch the toggle on, but this toggle is not displayed at all.

Are there any specific requirements to meet for imported certificate to show in this list?

I tested different key length (2048, 4096), validity (10 years, 1 year) and signing protocol (sha256, sha512), with no luck.

I have not been able to find any help on the Internet so far, apart from this article that does not help in this case, the toggle not showing up at all : https://support.apple.com/en-us/HT204477.

Thanks a lot for your help.