Update 2022/01/07: This question is over a year old now. Since then nothing has happened regarding the missing features, they are still missing ...
Since Microsoft decided to close the 5,085 votes voting which requested to add all the missing features to the linux client, and asked the community to vote again ...
Virtual background support for Linux: more than 1,830 votes
View more participants in Linux: more than 1220 votes
Together mode in Linux: more than 690 votes
just that we don't forget: @Sharon Zhao-MSFT said they will escalate it 339 days ago, until now nothing changed.
The last update was Sep 29th 2021. Is there any further development?!?