New Jar is out, updates the Fan bridge device type , also upgrades to the latest matter.js which has some connection improvements.
@ranielsen try this for your fan
Switch ceilingFan "Ceiling Fan" {matter="Fan, onOff.onOff"}
This forgoes needing a group and creates a Fan device that reacts to ON/OFF, Alexa successfully uses this for the “ON/OFF” voice command and in the UI.