I just had my note9 and apps are prompting for update. bixby home and vision were a breeze but when I updated bixby voice it tells "failure to install. try later". after several attempts using suggestions i got from online that all didn'twork. then, I don't know how or why but what I did was this: I updated first the Galaxy App, after that I tried updating bixby voice and voila! it worked! then it started downloading bixby service with bixby voice. bixby voice is working now.
Mine was hung up one oneUI. I updated that, rebooted, and then tried to buy a $1.00 theme. The purchase does not have to complete. Just the attempt triggers everything else to update. Best wishes.