It's only 20% rolled out so it's not available to everyone yet.
(It is interesting that your watch reported "download successful" as opposed to "no updates available". Iirc that was a known bug, but it's not happening for me with 20.26)
I was able to manually update, garmin express didn't work last night but wifi update today did. Averaging .35% per hour, will update later. Drained 5% just over night pre update
Hu Gyus, after the my successful Upgrate to 20.29 the watch still displass download the new software without installing anything. It used to tell no updates available in the past but this seems to be changed. Could you confirm this?