Users in western countries do not use 2 SIM cards mostly , in fact in many countries single SIM variants are sold.
Users are unaware of thing called as Dual SIM phones OR they do not need.
It is very bad trend going on to remove useful, basic features to so called simplify UI design.
Dear Samsung Member,
Greetings from Samsung Customer Support!
We have noted down the feedback regarding this and providing a continues great experience to our customer is our first priority. We would take this feedback for further improvements in our upcoming software launches.
Thank you for writing to Samsung.
Samsung Customer Support
Hello All - I'm happy to help any Friend that has a Samsung Dual SIM device!!
FYI, I'm from Toronto, Canada and my Samsung Dual Sim Note 10+ device MODEL NUMBER: SM-N975F/DS is an international import (I believe from Samsung Vietnam). I use SIM1 (Network Provider: BELL Canada) for work purposes and SIM2 (Network Provider: Rogers) for personal use. After running out of patience waiting many months for Samsung to fix this issue in UI 3.0, well, on March 4th 2021, I decided to revert back to Android 10, UI 2.5. Since then, my device is back to normal and working perfectly fine. Just like everyone here and many other similar threads for same issue, now I'm just monitoring every Samsung Community daily and waiting for someone to eventually post good news that Samsung has fixed this issue in Android 11, UI 3.x. Meanwhile, the best part is I have my SIM1 + SIM2 buttons for calls and messages! Since I'm in Canada, Samsung Members app will only connect to a local country, so when I posted a this issue in Samsung Community in Canada, fortunately and so lucky that I got help from an Expert Level 5 (CHMultimedia) who did me the huge favor uploading Authentic Samsung Software files and instructions with screenshots to his OneDrive. Please see below.
WARNING / CAUTION - PLEASE READ FIRST:
#1. Below recommended solution will only work for: SAMSUNG DUAL SIM NOTE10+ MODEL NUMBER: SM-N975F/DS
IF YOU HAVE A DIFFERENT MODEL NUMBER THEN STOP AND GET THE AUTHENTIC SAMSUNG SOFTWARE FILES THAT ARE SPECIFICALLY FOR YOUR DEVICE MODEL (sorry, I have no idea where someone would get Samsung Software files for a Dual SIM Note 10, S10, S10+, S20, Note20, Note20+, etc)
#2. BACKUP ALL YOUR DATA - ie. contacts, messages, calls, apps, and all types of media - images, videos, docs, etc....as this process will wipe out the data on your device!
For the SOLUTION to revert your Samsung Dual SIM Note10+ Model Number: SM-N975F/DS back to Android 10, UI 2.5, go to my post in SAMSUNG CANADA COMMUNITY (link below):
GOOD LUCK !!!
Farooq aka @Samsung_wXTp5Su