I am a current Xbox Gold subscriber, and have previously taken advantage of the trick to upgrade my account to Ultimate for $1 ( some years back). I tried to do the trick again tonight, and it worked it for me. I think they have a $1 for 3 months offer that lasts a few more days. I was able to add a 12 month Gold voucher to my account to take it to 2023, and that has now been converted to Ultimate for $1. (Next charge of $15.95 on 6/14/2023)
Hope this helps anyone else looking to upgrade. Best of luck.