This is something used mostly by companies. It is completely crazy to use shared mailboxes with this design!!!
The CEO of the company I manage turned on the new outlook by mistake, having 8 shared boxes and 4 full accounts it was a huge mess, it was immediately requested to the IT toi set things back to the old version and suggested to look for a alternative program...
I don't get how Microsoft plan things but this look as a HUGE step back and lately most of the developments seem to forget many users are inside a company where the things need to be stable and working all we see is useless stuff even on Windows Pro so I wonder what is this "vision" for the future...
But wait they created a Copilot new key, hope it can run over the "bad decisions team"