I was a gomuks user in the past, so recently when setting up Matrix again I decided to try https://iamb.chat and I love it.
It has a very minimal UI. You can set up a layout, exit and by default it will remember it.
Controls are vim-like all the way to macros. You can have tabs for things like rooms, DMs, the room list, and you can further split tabs into panes.
After tweaking the space taken by the usernames on left side of chat, I now have a compact Matrix monitor on my terminal.