Hey @S Sangar, welcome to the Sonos Community!

Sorry to hear Alexa did not want to speak to you from the Arc Ultra on first attempt, but great stuff figuring out this workaround.

Having had trouble adding Alexa to my system in the past as well, I know that being logged in to another Amazon app on the controller device can be a hurdle and removing those apps temporarily is a viable step to take.

Thanks again for sharing and I hope you continue to enjoy your Sonos system!