Recover configuration profiles installed on iOS and use them for digital signature

I have an application developed in QT in C++ and using Objective-C++ (.mm) as the native language for compiling IOs.

In this application I need to access the configuration profiles installed on the iPhone (e.g. -> .pfx digital certificate) as I do successfully on MacOS using the keychain certificate.

I am using the following code to try to search for the certificate in my .mm file:

        NSDictionary *query = @{
            (id)kSecClass:     (id)kSecClassCertificate,
            (id)kSecMatchLimit: (id)kSecMatchLimitAll,
            (id)kSecReturnRef: @YES,
        };

       CFTypeRef result = NULL;
       OSStatus status = SecItemCopyMatching((CFDictionaryRef)query, &result);

       if (status == errSecSuccess) {
           NSArray *response = (__bridge_transfer NSArray *)result;
           for (id r in response) {
               qDebug() << "ok";
           }
       } else {
           qDebug() << "error certificate: " << status;
       }

Running this code always returns: error certificate: -25300 (errSecItemNotFound). Even with configuration profiles installed on the iPhone, they are listed in the tab VPN Management and Device -> Configuration Profiles.

I would like to clarify some points such as:

1. Is it possible to access the certificates installed on the IOs, list them and use them in digital signatures as I have already done successfully on MacOS (using the <Security/Security.h> lib in C++)?

2. If it is possible, what would the code be like to list the installed configuration profiles and use their private key to sign the hash of a document?

3. Is there any further configuration needed in the project architecture? For example: In XCode, I went to target -> Capability -> I added the Keychain sharing capability.