Please allow users the capability to adjust the sidebar size in Microsoft Teams
Hope we can adjust the sidebars in Microsoft Teams, or have the option to have a full screen version of the Teams window.
Sean Ellis commented
Improving the layout and density of the UI is a popular request. You may also wish to support the "Compact layout" thread at https://microsoftteams.uservoice.com/forums/555103-public/suggestions/17408641-please-create-a-professional-compact-chat-layout