Just wanted to share this info if in case somebody is looking for it.
This is by using activity launcher app from the playstore
Disclaimer: Be careful using activity launcher app, if you don't know what function does, don't press on it.
Here is the screenshot of the hidden Samsung network settings
To access this , download activity launcher from playstore and type hiddennetworksetting, you will see an activity under call setting.
Here is all list of bands that available on Canadian S21Ultra:
Hope this is informative.
