From RN 1.14:

• With this update, OpenShift Pipelines supports horizontal pod autoscaling for the Operator proxy webhook. If the pod that runs the Operator proxy webhook reaches 85% CPU utilization, the autoscaler creates another replica of the pod. If you want to use more than one replica for the Operator proxy webhook at startup, you must configure this number in the options.horizontalPodAutoscalers spec of the TektonConfig CR.

This probably needs to go into the "customizing configurations..." assembly, but I need to work out the user impact and also if the exact spec is right.