Removing the Conversation Tab is being reviewed by the feature team.
For deleting chat messages, please following progress here: https://microsoftteams.uservoice.com/forums/555103/suggestions/33535006.
An error occurred while saving the commentRae commented
Agreed. I want to move the Files tab to the first position and the conversations tab to the second position and can't figure out how. This causes a lot of confusion with my team.