The LTE updates get released or approved by the carriers from what I have read. I have the GW4 46mm LTE and just received the latest update yesterday. As far as notifications go not having the same problems as you are. Mine basically stay until I swipe right to clear all or I have cleared them from the phone. I had one yesterday I was trying to save for later, but at some point I cleared all from the phone which as I found later also must have cleared the watch.
I see Samsung released an update yesterday (https://doc.samsungmobile.com/SM-R895U/TMB/doc.html). Thank you Samsung Dev. Yesterday's update (which is similar to the bluetooth version released on 10/20/2021(https://doc.samsungmobile.com/SM-R890/XAA/doc.html)) should resolve the issue.