Yes, same google account on all devices. Using the ADB to disable doze helps. Gmail seems to be the only thing that is delayed that I'm aware of right now. I think it really is an Android issue more than a Samsung? Just my opinion.
I only have a Samsung s9 connected to my accounts,but goggle is connected to all of them.But to be honest this only started happening after the last update,everything was fine till then.
Thank you for your reply. Please don't misunderstand me, I'm not saying the issue is fixed for my Galaxy S9+ as the issue gradually comes back after some time (a night's sleep). I am also aware of what people have tried before, I read all posts. What I am trying to do is find a correlation between things I do and the situation getting better. Perhaps I can find a pattern after testing reminders/events programmed every 15 minutes for several days. I am not at all saying the issue is fixed for me, I'm only saying I suspect (am looking for) a correlation but will only know if I spend more days testing. Last but not least, my old Nexus 7 2013 tablet always delivers the same notifications (same Google account) exactly on time while my GS9+ is often several minutes late for the same notification.
I do. I have the same Google account on both a GS9+ and an old Nexus 7 2013. The Nexus always delivers calendar notifications on time, the S9+ has the same problem everyone has here.