Sadly you are discovering
That some work, some don't. And any discussion why some don't has never resulted in it working later because there are no changes the owner can make.
Besides putting in fresh batteries and being within a foot of the wireless keyboard dongle and trying the dongle in all USB ports.
I wish the news was better but while it was nice that the tv makers added this feature I'm beginning to wonder if they should have a 99 buck keyboard or higher price of their own label for those that don't want to try a few.