I cleaned the cache of sim toolkit under apps in settings. Since then it seems my phone is working as it should be. I'll keep you updated. I hate fact that latest software patch doesn't fix the issue on 1k€ phone.
I also have a note9 and have been having this issue since the December update. This is a complete joke. I am unemployed and looking for work. I cannot afford a new device. I need a bloody phone that can answer a call. Do you realise how ridiculous it sounds having to ask prospective employers to call but leave a message since my expensive "top of the range" phone does not allow me to be heard when answering a call?? This is simply unacceptable.
So I got very excited last week when I downloaded the last Samsung update. Finally this problem was fixed! I had 6 or so wonderful days without having to do the speaker activation work around. Sigh, today I find I now have the same problem back. I have done nothing different in the past week. Have not upgraded anything or got any new apps. Back to the too hard basket!
Samsung not showing responsibility at all. This has been going on since latter part of 2020 and they don't seem to care about the issue. Factory reset is not the solution. It seems to work for some, even so the problem returns. Is this their way of directing our attention to S21?