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 commentConnie Bonnici commented
I would like the option to remove or hide the conversations tab. Teams is a great way to post and link to team related spreadsheets or slideshows and doesn't require a chat function. Keeping one sometimes means there are chat posts that are missed because they are not expected.