Blockstorage v3 supports multiple different api calls for quality-of-service specifications. The full list to be added:

• List QoS Specifications
• Create a QoS specification
• Delete a QoS specification
• Show a QoS specification details
• Set keys in a QoS specification
• Unset keys in a QoS specification
• Associate QoS specification with a volume type
• Disassociate QoS specification from a volume type
• Disassociate a QoS specification from all associations
• Get all associations for a QoS specification

Docs for the api: https://docs.openstack.org/api-ref/block-storage/v3/index.html?expanded=#quality-of-service-qos-specifications-qos-specs
i'll be gradually working on this