I contacted my carrier (Verizon) and the rep I talked to contacted someone at Samsung, who told them that the beta program for the Note 10+ in the us is currently full, and they are not accepting any new devices into the program.
That doesn't mean they won't accept more devices at some point, so check your app once a week or so to see. There isn't any need to check multiple times a day as they don't update the app that often, once per day is more than enough.
That's all I know though.
Oh also if your looking for a us version of an app try searching Apkmirror.com. I've added a link below.