@bbildman I believe that only works for the specific shortcut you use to launch Opera, which isn't attached to the shortcut in the taskbar.
What worked for me is #1: Adding the system environment variable "OPERA_AUTOUPDATE_DISABLED" to my User variables, and then
#2: going to the program directory for opera, opening the folder that matches the version of Opera I like, and then renaming "opera_autoupdate.exe", "opera_autoupdate.licenses", "opera_autoupdate.version".
For me, it was ....AppData\Local\Programs\Opera\99.0.4788.9_3