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 commentAnonymous commented
Please add option to delete entire conversation, it is absolutely necessary to have.
Without this my teams is absolutely mess and it becomes really difficult to search for old messages in so much of unnecessary chats.