I'm using Xray Cloud app in Jira Cloud. I can use only 2 Xray entity properties in JQL Search in Jira (Enhanced querying with JQL - Xray Cloud Documentation - Xray (getxray.app)). Xray explains: "No specific JQL functions are provided, since Jira Cloud does not provide a mechanism to implement them."

I'd like to use specific JQL functions for Xray Cloud issues that are described here for Xray: Enhanced querying with JQL - Xray Server + DC - Xray (getxray.app)