What Is the Relationship between the Threshold ‘T’ and the Security Level of the Oracle?

The security level is directly proportional to the threshold T. A higher T (closer to N, the total number of nodes) requires an attacker to compromise more nodes to generate a false signature, making the attack more expensive and difficult. A lower T is more resilient to node failure (if a few nodes go offline, the oracle can still report) but is less secure against collusion.